ABSTRACTS

Il Nuovo Cimento D, Vol. D 13(5), 677-685 (1991)

Diode laser spectroscopy: water vapor detection in the atmosphere

A. Lucchesini, L. Dell'Amico, I. Longo, C. Gabbanini, S. Gozzini, L. Moi
Istituto di Fisica Atomica e Molecolare del CNR Via del Giardino 7 - 56127 Pisa - Italy

Abstract

Diode laser spectroscopy of water vapor has been performed in the near IR and the pressure broadening coefficients in nitrogen and in air have been measured for one roto-vibrational line. Detection of water vapor in the atmosphere has been obtained and an evaluation of the sensitivity of our apparatus is reported. Discussion for further improvements is made.

14 References.

(italian)

Atti del LXXVII Congresso Nazionale della Società Italiana di Fisica - L'Aquila, 30 Settembre-5 Ottobre 1991, p. 121

Spettroscopia a diodi laser del vapor d’acqua e del metano per il monitoraggio dell’atmosfera

A. Lucchesini, I. Longo, C. Gabbanini, S. Gozzini, L.Moi*
Istituto di Fisica Atomica e Molecolare del CNR
Via del Giardino, 7 - 56127 Pisa

*Dipartimento di Fisica - Università di Siena
Via Banchi di Sotto, 55 - 53100 Siena

Riassunto

Si presentano i risultati ottenuti con la tecnica spettroscopica in assorbimento a modulazione di frequenza utilizzante diodi laser. Tale sistema risulta essere adatto alle situazioni per le quali è richiesta una notevole sensibilità ed una estrema compattezza. In vista di una utilizzazione per il monitoraggio ambientale, vengono mostrate le misure di assorbimento di vapor d’acqua nello spettro roto-vibrazionale overtone che si colloca ad 820 nm [1], come pure le righe di combinazione overtone del metano ad 860 nm. Sono poi mostrati i risultati delle misure di allargamento di riga all’aumentare della pressione dei gas da 20 Torr fino a pressione atmosferica.

------
¹ A. Lucchesini, L. Dell’Amico, I. Longo, C. Gabbanini, S. Gozzini, L. Moi, Diode laser spectroscopy: water vapour detection in the atmosphere”, Nuovo Cimento D 13(5), 677-685 (1991).

"High-Performance Optical Spectrometry": SPIE International Conference held in Warsaw, Poland, 1-5 June, 1992

Proceedings SPIE, Vol. 1711, 271-281 (1993)

Diode laser overtone spectroscopy: a possible atmospheric monitoring technique

A. Lucchesini, I. Longo, C. Gabbanini, S. Gozzini
Istituto di Fisica Atomica e Molecolare del CNR - Via del Giardino, 7 I-56127 Pisa, Italy
L. Moi
Dipartimento di Fisica, Università di Siena - Via Banchi di Sotto, 55 I-53100 Siena, Italy

Abstract

By the use of commercial AlGaAs diode lasers and short radiation path-length, frequency modulation (FM) absorption spectroscopy has been performed in the near infrared to study the overtone absorption bands of molecules interesting as environmental sensing tracers. The measurements concern water vapor resonances around 820 nm, methane around 780 nm and 860 nm, and ammonia around 790 nm. Pressure broadening coefficients have been extracted by using different buffer gases like air, N₂, He, and by varying their pressure between 10 and 760 Torr. A χ² fitting of the absorption line shapes has been used for this purpose by the aid of a simple fitting function. Finally an estimation of the sensitivity of the technique is made.

22 References.

Applied Optics, Vol. 32(27), 5211-16 (1993)

Diode Laser Spectroscopy of Methane Overtone Transitions

A. Lucchesini, I. Longo, C. Gabbanini, S. Gozzini And L. Moi^
Istituto di Fisica Atomica e Molecolare del CNR - Via del Giardino, 7 I-56127 Pisa, Italy
^ Dipartimento di Fisica, Università di Siena - Via Banchi di Sotto, 55 I-53100 Siena, Italy

Abstract

With the aid of commercial room temperature AlGaAs diode lasers, frequency modulation (FM) absorption spectroscopy was performed on the 790 nm and 860 nm rovibrational combination overtone bands of methane. Three weak transitions are reported in the range around 861 nm that, to our knowledge, have not yet been observed and measured. Self-broadening and pressure-broadening coefficients of one of these new absorption features (at 860.893 nm) were derived from CH₄ and for CH₄ immersed in N₂ and He buffer gases. An evaluation of the methane detection sensitivity is given for favorable laboratory conditions as well as for an open-path situation.

KEY WORDS: Diode laser spectroscopy, overtone absorption spectroscopy, environmental Control

19 References.

(italian)

Atti del LXXIX Congresso Nazionale della Società Italiana di Fisica - Udine, 27 Settembre-2 Ottobre 1993, p. 227

Spettroscopia FM a due toni per il monitoraggio ambientale

A. Lucchesini, D. Pelliccia, I. Longo, C. Gabbanini, S. Gozzini
IFAM - CNR Pisa

Riassunto

La facile modulabilità della frequenza d'emissione dei diodi laser, tramite la loro corrente d'iniezione, li rende adatti all'uso delle tecniche di rivelazione elettro-ottiche. In questo lavoro si presentano i risultati ottenuti con le tecniche della spettroscopia laser di assorbimento. Il laser viene modulato a due frequenze 1 GHz ± 10 MHz ed il segnale e' ottenuto rivelando il battimento a 20 MHz. Sintonizzandosi sulle righe rotovibrazionali overtone dei gas NH₃ e C₂H₂, viene evidenziata la buona selettività di tale metodologia, dovuta alla elevata risoluzione spettrale del sistema (Δν / ν ~10^-9) anche in condizioni sfavorevoli, come quelle di una stazione mobile di monitoraggio ambientale.

Il Nuovo Cimento D, Vol. D 16(2), 117-126 (1994)

Diode Laser Spectroscopy of Ammonia Overtone Transitions

A. Lucchesini, D. Pelliccia, C. Gabbanini, S. Gozzini, And I. Longo
Istituto di Fisica Atomica e Molecolare del CNR - Via del Giardino 7, I-56127 Pisa, Italy

Summary. --- Diode laser spectroscopy of ammonia ro-vibrational overtone transitions has been performed in the near IR, by using direct absorption, wavelength modulation, and two-tone frequency modulation techniques. Pressure broadening coefficients in air, hydrogen, helium and self-broadening have been measured. The high sensitivity of the apparatus permitted the detection of 70 ppm of NH₃ in air per meter of path at atmospheric pressure. New lines have been observed in the 790 nm band.

Riassunto. --- Tramite le tecniche di assorbimento diretto, di modulazione di lunghezza d'onda e di modulazione di frequenza a due toni è stata effettuata una spettoscopia a diodi laser delle transizioni overtone roto-vibrazionali dell'ammoniaca nel vicino IR. Sono stati misurati i coefficienti d'allargamento per pressione in aria, idrogeno, elio e di autoallargamento. L'alta sensibilità dell'apparato ha permesso la rivelazione di 70 ppm di ammoniaca in aria per metro di percorso a pressione atmosferica. Nella banda a 790 nm sono state identificate due nuove righe.

13 References.

"Optical Spectroscopic Techniques and Instrumentation for Atmospheric and Space Research": the SPIE's Annual Meeting held in San Diego 24-29 July, 1994

Proceedings SPIE, Vol. 2266, 500-509 (1994)

Diode Laser Overtone Spectroscopy of Atmospheric Trace Species

A. Lucchesini, D. Pelliccia, I. Longo, C. Gabbanini, S. Gozzini
Istituto di Fisica Atomica e Molecolare del CNR - Via del Giardino, 7 I-56127 Pisa ITALY

Abstract

This work is based on the use of diode lasers as spectroscopic sources for the observation and study of weak overtone bands of the NIR. The diode laser emission wavelength can be scanned around a gas resonance by sweeping its injection current, permitting a direct observation of an absorption line-shape. The resolution is limited principally by the effective laser linewidth, generally ~20 MHz in free running mode. The signal-to-noise ratio is increased by using the frequency modulation technique, and the excess laser amplitude 1/f noise is reduced by working at high frequencies. Since detectors operating at high frequencies are expensive and less sensitive, a good compromise is the two-tone frequency modulation technique, which uses two close high frequencies and collects the beat signal at lower frequency. Pressure broadening coefficients have been measured for some acetylene and ammonia absorption lines in the 790 nm bands and new lines have been observed. Pressure shift of two acetylene lines have been examined. It is shown that this spectroscopic apparatus can extract very weak signals from the background and can be a good choice when the space occupied by the spectrometer needs to be restricted into small volumes.

Keywords: optical spectroscopy and spectrometers, diode laser spectroscopy, frequency modulation spectroscopy, atmospheric monitoring

17 References.

PRINCIPAL AUTHOR BIOGRAPHY

Dr. Alessandro Lucchesini took his Laurea Degree in Physics by the University of Rome "La Sapienza" in 1983 studying amorphous silicon optoelectronic devices. He worked for four years as Researcher in Rome by the Solid State Electronic Institute (IESS) of the National Research Council (CNR) of Italy, and in 1986 and 1987 he was Research Associate in the Engineering Dept. of the University of Colorado at Boulder. In 1990 he joined the "laser spectroscopy" group of the Institute of Atomic and Molecular Physics (IFAM) of CNR in Pisa, where he still operates in the field of laser interaction with gases.

(italian)

Atti del LXXXI Congresso Nazionale della Società Italiana di Fisica - Perugia, 2 - 7 Ottobre 1995, p. 21

Spettroscopia a diodi laser per l'analisi delle righe overtone dell'acetilene

A. Lucchesini, M. De Rosa, A. Ciucci, D. Pelliccia, C. Gabbanini, S. Gozzini
Istituto di Fisica Atomica e Molecolare del CNR, Pisa
Via del Giardino, 7 - 56127 Pisa

Riassunto

Un sistema spettroscopico a sorgenti accordabili e modulabili in frequenza come quello utilizzante i diodi laser si mostra molto adatto a risolvere ed analizzare gli assorbimenti di gas atomici e molecolari nell'infrarosso. In particolare, utilizzando diodi laser ad eterogiunzione di tipo commerciale, è possibile osservare le righe roto-vibrazionali overtone di gas come Rb, Cs, CH₄, NH₃, H₂O e C₂H₂. Dell'acetilene sono state da noi localizzate una quarantina di righe e sulle più intense sono state effettuate analisi di riga a varie pressioni del gas e ricavati i coefficienti di allargamento e di shift. I dati relativi alle misure di assorbimento diretto e di rivelazione in fase sulla 1^a e sulla 2^a armonica sono stati elaborati tramite programmi di analisi e di fit realizzati appositamente.

Applied Physics B, Vol.63(3), 277-282 (1996)

Diode Laser Spectroscopy of Overtone Bands of Acetylene

A. Lucchesini, M. De Rosa, D. Pelliccia, A. Ciucci, C. Gabbanini, S. Gozzini
Istituto di Fisica Atomica e Molecolare del CNR - Via del Giardino, 7 I-56127 Pisa, ITALY

Abstract

Overtone absorption lines of acetylene in the regions around 12700 and 11800 cm^-1 have been examined by the use of tunable diode lasers in free-running mode. The diode laser emission wavelength was scanned around the gas resonances by simply sweeping its injection current, permitting a direct observation of the absorption line-shapes. Weak overtone absorption lines have been detected by using the wavelength modulation (WM) spectroscopy with 2^nd harmonic detection technique and the collisional broadening and shift coefficients have been obtained. The high resolving power and accuracy of the spectrometer permitted a wavenumber error of less than 0.01cm^-1. The correct interpretation of the absorption signals when detecting the second harmonic in the presence of a sloping background is discussed.

PACS: 07.65.Gj, 33.70.Jg

17 References.

13^th International Conference on "Spectral Line Shapes", Florence, Italy, June 16-21, 1996

AIP Conference Proceedings, Vol. 386, 367–368 (1997)

COLLISIONAL BROADENING AND SHIFT OF ACETYLENE AND OXYGEN OVERTONES

A. Lucchesini(*), M. De Rosa(*), A. Ciucci(*), C. Gabbanini(*), S. Gozzini(*)

Abstract

Some overtone absorption lines of acetylene and oxygen in the region around 12000 and 13000 cm^-1 respectively have been examined by using a diode laser (DL) spectrometer. The high resolving power (~10⁷) of the spectrometer permits the detection and the study of the absorption features of the molecules. By sweeping the DL injection current a corresponding frequency sweep around the gas resonances have been achieved with a precision of less than 0.01 cm^-1. The DL sources have been used in free-running mode and their gross tuning on the sample resonances have been obtained by changing their temperature and controlling it within 0.02 K. Unfortunately a peculiarity of these sources is the amplitude modulation (AM) associated to the frequency modulation (FM). Its typical behaviour has to be taken into account when analizing the results. In this work the FM spectroscopy along with the 2^nd harmonic detection techniques have been adopted in order to maximize the signal to noise ratio (S/N) and to extract the necessary informations either on the line width and on the line position for each resonance. The fit procedure has been critically analyzed to take into consideration the instrumental effects. The results are compared with the ones got by the direct absorption (DA) measurements.

----------------------------------

(*) IFAM – CNR - Via del Giardino, 7, I-56127 Pisa, Italy

(italian)

Atti del LXXXIII Congresso Nazionale della Società Italiana di Fisica - Como, Villa Olmo, 27 - 31 ottobre 1997, p. 91

Studio delle righe d’assorbimento dell’ossigeno nella banda atmosferica A

A. Lucchesini, M. De Rosa , A. Ciucci, C. Gabbanini E S. Gozzini
IFAM-CNR, Via del Giardino 7, I-56127 Pisa, Italy

Riassunto

Tramite un sistema spettroscopico a diodi laser ad eterogiunzione, sorgenti facilmente accordabili e modulabili in frequenza, è stata studiata la banda d’assorbimento dell’ossigeno molecolare che si colloca attorno ai 760 nm. In particolare, tramite la tecnica Wavelength Modulation Spectroscopy, è stato osservato il comportamento di tali righe roto-vibrazionali elettroniche al variare della pressione del gas stesso e di altri gas ospiti. I risultati delle misure ottenute con il metodo di rivelazione in fase sulla 2^a armonica sono stati analizzati ed elaborati tramite appositi algoritmi che hanno permesso di ricavare i coefficienti di allargamento e di shift per alcune righe.

Il Nuovo Cimento, Vol. D 20(3), 253-260 (1998)

Diode laser spectroscopy of oxygen electronic band at 760 nm

A. Lucchesini, M. De Rosa, C. Gabbanini, S. Gozzini
Istituto di Fisica Atomica e Molecolare del CNR - Via del Giardino, 7 I-56127 Pisa, Italy

Abstract

Collisional broadening and shift coefficients have been obtained by analyzing the line shapes of oxygen absorptions in the 760 nm electronic band. By using a diode laser spectrometer with commercially available etherostructure Al_xGa_1-xAs diode lasers operating in "free-running mode", line shape parameters have been collected at room temperature by varying the gas pressure. A systematic study has been carried on seven absorption lines by scanning the diode laser emission wavelength around the gas resonances. The weak absorption lines have been detected by using the wavelength modulation (WM) spectroscopy technique with 2nd harmonic detection.

PACS: 33.70.Jg: Lines and bands widths, shapes, and shifts. 33.20.Ea: Infrared spectra. 07.57.Ty: Infrared spectrometers, auxiliary equipment, and techniques.

16 references.

Optics Communications, Vol. 147(1-3), 55-60 (1998)

On the measurement of pressure induced shift by diode lasers and harmonic detection

M. De Rosa, A. Ciucci, D. Pelliccia, C. Gabbanini, S. Gozzini, and A. Lucchesini
Istituto di Fisica Atomica e Molecolare del CNR - Via del Giardino, 7 I-56127 Pisa Italy

Abstract

In this paper we present an analysis of the line shape of the ro-vibrational molecular absorptions, in case of frequency modulation spectroscopy with diode lasers, and in presence of a residual amplitude modulation. Subtle effects, such as pressure induced shift, can be measured with sufficient accuracy also for the weak transition lines of the overtone and the combination bands of the molecules, under the proviso of considering the correct fit function in order to avoid possible systematic errors. Some results are given for acetylene overtone absorptions in the derivative spectroscopy limit (small amplitude of modulation) and in the case of large amplitude of modulation.

Keywords = Spectral line shapes; Diode laser spectroscopy; Frequency modulation spectroscopy

PACS 33.70.Jg, 07.57.Ty

21 References.

(italian)

Atti del LXXXV Congresso Nazionale della Società Italiana di Fisica - Pavia, 20 - 24 Settembre 1999, p. 146

Spettroscopia a diodi laser per l'analisi dele righe overtone dell'acetilene

A. Lucchesini, S. Gozzini, C. Gabbaniini
Istituto di Fisica Atomica e Molecolare del Consiglio Nazionale delle Ricerche
Via del Giardino, 7 - 56127 Pisa

Riassunto

Tramite una sorgente laser a diodo sono state osservate varie righe d'assorbimento overtone del vapor d'acqua nell'intorno di 825 nm. Con la tecnica della modulazione di lunghezza d'onda e rilevando il segnale in fase sulla seconda armonica è stato analizzato il comportamento di tali righe al variare della pressione di alcuni gas tampone e si sono ricavati i coefficienti d’allargamento e di shift collisionali a temperatura ambiente. A tale scopo nel fit dei dati sperimentali si è tenuto conto della modulazione di ampiezza associata a quella di lunghezza d'onda, tipica dei diodi laser. Sono mostrati i risultati ed un confronto con quelli ottenuti con altri sistemi spettroscopici.

The European Physical Journal D, Vol. 8(2), 223-226 (2000)

Water vapor overtones pressure line broadening and shifting measurements

A. Lucchesini, S. Gozzini, C. Gabbanini
Istituto di Fisica Atomica e Molecolare del Consiglio Nazionale delle Ricerche
Via del Giardino 7, I-56127 Pisa - Italy

Abstract

By using a spectrometer having as source a commercial etherostructure AlGaAs diode laser operating in "free-running mode", line shape parameters of some water vapor ro-vibrational overtones at 820-830 nm have been measured at room temperature. These weak absorption lines have been detected by using the wavelength modulation spectroscopy technique with second-harmonic detection. The broadening and shifting coefficients have been obtained by fitting the collected second-harmonic absorption features while varying the pressure of different foreign gases.

PACS: 33.70.Jg - Line and band widths, shapes, and shifts. 33.20.Ea - Infrared spectra. 07.57.Ty - Infrared spectrometers, auxiliary equipment, and techniques.

12 references.

15^th International Conference on Spectral Line Shapes (ICSLS XV), Berlin, Germany, 10-14 July 2000

AIP Conference Proceedings Vol. 559, 331–333 (2001)

Pressure Line Broadening And Shifting of Water Vapor Overtones

A. Lucchesini, S. Gozzini
IFAM - CNR - Area della Ricerca di Pisa - Via Alfieri, 1 (Loc. San Cataldo)
I-56010 Ghezzano - San Giuliano Terme (PI) - Italy

Abstract

Some overtone absorption lines of water vapor in the region around 12100 cm^-1 have been examined by using a diode laser (DL) spectrometer [1]. The employed sources are commercially available double heterostructure Al_xGa_1-xAs DLs operating in "free-running" mode; still the high resolving power (~10⁷) of the spectrometer permits the detection and the study of the absorption features of the molecules with a precision of less than 0.01 cm^-1. Wavelength modulation spectroscopy (WMS) along with the 2nd harmonic detection techniques have been adopted in order to maximize the signal to noise ratio (S/N) and to extract the necessary informations either on the line width and on the line position for each resonance. The fit procedure has been critically analyzed in order to take into account the instrumental effects and the amplitude modulation (AM) always associated to the frequency modulation (FM) of these sources [2]. Collisional broadening and shifting coefficients by three different perturber gases have been measured at room temperature. The results are compared to those obtained by more expensive spectroscopic systems.

1. A. Lucchesini, S. Gozzini, C. Gabbanini, Eur. Phys. J. D, Vol. 8, 223-226 (2000)
2. M. De Rosa, A. Ciucci, D. Pelliccia, C. Gabbanini, S. Gozzini, A. Lucchesini, Opt. Commun., Vol. 147, 55-60 (1997)

(italian)

Atti del LXXXVII Congresso Nazionale della Società Italiana di Fisica - Milano, 24-29 Settembre, 2001, p. 114

Ligth-Induced Atomic Desorption (LIAD) del potassio in film di siloxano

S. Gozzini, A. Lucchesini
Istituto di Fisica Atomica e Molecolare, Area della Ricerca del CNR, Pisa

Riassunto

In questa comunicazione vengono presentate alcune misure dell'effetto di desorbimento atomico del potassio indotto da radiazione non risonante in celle di misura sigillate. L'effetto è stato studiato in celle di Pyrex contenenti potassio e rivestite internamente di poli-dimetilsiloxano (PDMS). Sotto illuminazione non risonante a varie lunghezze d'onda ed a diverse potenze si è osservato un aumento della concentrazione del potassio nella cella. La concentrazione è stata monitorata tramite spettroscopia a diodi laser in assorbimento sulla riga D₁ dell'elemento. Vengono anche mostrate misure sui tempi tipici d'attivazione e di rilassamento del fenomeno.

The European Physical Journal D, Vol. 22, 209-215 (2003)

Collisional broadening and shifting of ammonia absorption lines at 790 nm

A. Lucchesini and S. Gozzini
Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche
Area della Ricerca di Pisa, Via G. Moruzzi 1, 56124 Pisa - Italy

Abstract

By using a diode laser spectrometer based on a commercial heterostructure diode laser operating in "free-running" mode, line shape parameters of some ammonia ro-vibrational overtones at 790 nm have been measured at room temperature. These weak absorption lines have been detected by using the wavelength modulation spectroscopy technique with second-harmonic detection. The broadening and shifting coefficients have been obtained for ten absorption lines by fitting the collected second-harmonic absorption features and varying the pressure of different buffer gases.

PACS: 33.70.Jg - Line and band widths, shapes, and shifts; 33.20.Ea - Infrared spectra; 07.57.Ty - Infrared spectrometers, auxiliary equipment, and techniques.

18 references.

(italian)

Atti del XC Congresso Nazionale della Società Italiana di Fisica - Brescia, 20-25 Settembre 2004, p. 107

Spettroscopia overtone dell'anidride carbonica e dell'etilene tramite laser a diodo

A. Lucchesini, S. Gozzini
Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche - Area della Ricerca di Pisa

Riassunto

Viene presentato un lavoro di spettroscopia fine su molecole d'interesse ambientale come l'anidride carbonica e l'etilene realizzato per mezzo di sorgenti laser a diodo commerciali e di tecniche di modulazione di frequenza e di rivelazione in fase. Si mostrano i risultati delle misure effettuate su alcune righe d'assorbimento attorno a 11810 cm^-1 (846 nm) per il C₂H₄ e 12770 cm^-1 (783 nm) per il CO₂ con un errore massimo di 0.01 cm^-1 (potere risolutivo dello spettrometro ~10⁷) prendendo come riferimento le righe d'assorbimento dello iodio molecolare. Nel caso del CO₂ vengono date le classificazioni rotazionali fino a J = 48 e ricavati i relativi parametri roto-vibrazionali.

The European Physical Journal D, Vol. 28(2), 157-162 (2004)

Light-induced potassium desorption from polydimethylsiloxane film

S. Gozzini, A. Lucchesini
Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche
Area della Ricerca - Via G. Moruzzi 1, 56124 Pisa - Italy

Abstract

Potassium photoejection from polydimethylsiloxane surfaces has been observed and analyzed in detail. By diode laser absorption spectroscopy the K concentration in a sealed measurement cell without buffer gas has been monitored as a function of the environment variables, like temperature, flooding light wavelength and power. The dynamic evolution of the process has been measured too, showing differences compared to previous measurements with different alkali-metal atoms. Saturation spectroscopy on the K D₁ line has been performed at room temperature by taking advantage of this phenomenon.

PACS: 34.50.Dy - Interactions of atoms and molecules with surfaces; photon and electron neutralization of ions, 42.50.Ct - Quantum description of interaction of light and matter; related experiments, 68.43.Tj - Photon stimulated desorption

16 references.

Spectrochimica Acta A, Vol. 60(14), 3381-86 (2004)

Diode Laser Spectroscopy of Ammonia and Ethylene Overtones

A. Lucchesini, S. Gozzini
Istituto per i Processi Chimico-Fisici del CNR, Area della Ricerca
Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

Some overtone absorption lines of ammonia and ethylene have been examined by using a tunable diode laser (TDL) spectrometer in the region around 12650 and 11800 cm^-1 respectively. The spectrometer sources are commercially available double heterostructure InGaAlAs and AlGaAs TDLs operating in the "free-running" mode. The high resolving power (~10⁷) of the spectrometer permitted the detection and the study of the line positions of such molecules with a precision better than 0.01 cm^-1. In order to maximize the signal to noise ratio and to extract the necessary informations either on the line width and on the line position for the detected molecular resonances, the wavelength modulation spectroscopy (WMS) along with the 2^nd harmonic detection techniques have been applied. For this purpose the fitting procedure took into account the instrumental effects and the amplitude modulation (AM) always associated with the frequency modulation (FM) of these type of sources. This technique permitted also the measurement of the collisional broadening and shifting coefficients by different buffer gases at room temperature.

Keywords: Overtone absorption spectroscopy; Tunable diode laser spectrometer; Line widths and shapes; Pressure-broadening coefficients

34 references

MMD Meeting 2005 - Poster Session B 53 - 22 June 2005

Diode laser spectroscopy of carbon dioxide at 780 nm and methane at 840 nm.
A. Lucchesini, S. Gozzini
IPCF - CNR - Pisa - Italy

Abstract

Overtone absorption lines of carbon dioxide and methane have been examined by using a diode laser (DL) spectrometer in the region around 12800 and 11900 cm^-1 respectively. The spectrometer uses commercially available double heterostructure InGaAlAs and AlGaAs DLs sources operating in "free-running" mode. In order to detect these very weak "overtone" features the sensitivity of the apparatus is increased by the use of the wavelength modulation spectroscopy (WMS) with the phase detection technique and a long optical path length obtained by using a Herriott type measurement cell. By this way the minimum detected absorption coefficient was 1.4 x 10^-8 cm^-1. These techniques permitted also the measurement of some collisional broadening and shifting coefficients by different buffer gases at room temperature. For this purpose a fit procedure that takes into account the instrumental effects has been adopted. The resolving power (~10⁷) of the spectrometer allowed the detection of the absorption resonance positions with a maximum error of 0.01 cm^-1. This let us obtain the CO₂ band parameters with a good precision.

Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 96(2), 289–299 (2005)

Special issue: The HITRAN Molecular Spectroscopic Database, Edited by L.S. Rothman, K. Chance, A. Goldman and C.P. Rinsland

Diode Laser Overtone Spectroscopy of CO₂ at 780 nm

A. Lucchesini, S. Gozzini
Istituto per i Processi Chimico-Fisici del CNR, Area della Ricerca, Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

Overtone absorption lines of ¹²C¹⁶O₂ have been examined by using a tunable diode laser (TDL) spectrometer in the region around 12770 cm^-1. The spectrometer sources are commercially available double heterostructure InGaAlAs TDLs operating in the "free-running" mode, which allowed the detection of the line positions within 0.01 cm^-1. The observed carbon dioxide absorption lines belong to the ν₁ + 5ν₃ ro-vibrational band with rotational quantum number J up to 48. The minimum absorbance detected by the spectrometer (~5 x 10^-6) permitted to observe the weakest lines having the absorption cross section of the order of ~1 x 10^-27 cm²/molecule.

Keywords: Carbon dioxide, Overtone absorption spectroscopy, Tunable diode-laser spectrometer

29 references

Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 103(1), 209–216 (2007)

Methane Diode Laser Overtone Spectroscopy at 840 nm

A. Lucchesini, S. Gozzini
Istituto per i Processi Chimico-Fisici del CNR, Area della Ricerca, Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

Overtone absorption lines of ¹²CH₄ have been examined by using a tunable diode laser (TDL) spectrometer in the region around 11900 cm^-1 (840 nm) where the combination overtone band ν₁ + 3ν₃ lies. The spectrometer sources are commercially available heterostructure GaAlAs TDLs operating in the “free-running” mode, which allowed the detection of the line positions within 0.01 cm^-1. The wavelength modulation spectroscopy (WMS) and the 2nd harmonic detection technique permitted the measurements of minimum absorbances of the order of ~5 x 10^-6. This allowed to observe the weakest lines of the band with absorption cross sections of the order of ~2 x 10^-25 cm²/molecule or ~0.5 km^-1/amagat. For some of them self-, air-, He- and H₂-broadening coefficients have been obtained at room temperature.

Keywords: Methane absorption coefficients, Overtone bands, Tunable diode-laser spectrometer

22 references

Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 103(1), 74–82 (2007)

Diode Laser Spectroscopy of CO₂ at 790 nm

A. Lucchesini, S. Gozzini
Istituto per i Processi Chimico-Fisici del CNR, Area della Ricerca, Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

Absorption lines of ¹²C¹⁶O₂ have been examined by using a tunable diode laser spectrometer in the region around 12670 cm^-1 (790 nm). The spectrometer sources are commercially available double heterostructure InGaAlAs tunable diode lasers (TDLs) operating in the "free-running" mode, which allowed the detection of the line positions within 0.01 cm^-1. The observed carbon dioxide absorption lines belong to the combination overtone 2ν₂ + 5ν₃ ro-vibrational band with intensities ranging around 10^-28 cm/molecule.

Keywords: Carbon dioxide, Overtone absorption spectroscopy, Tunable diode-laser spectrometer

18 references

(italian)

Atti del XCII Congresso Nazionale della Società Italiana di Fisica - Torino, 18-23 Settembre 2006, p. 10

Spettroscopia in assorbimento overtone dell'anidride carbonica con l'uso di laser a diodo

A. Lucchesini, S. Gozzini
Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche - Area della Ricerca di Pisa

Riassunto

Nella comunicazione viene presentato un lavoro di spettroscopia fine sulla molecola anidride carbonica realizzato per mezzo di uno spettroscopio a sorgenti laser a diodo commerciali e di tecniche di modulazione di frequenza e di rivelazione in fase. Si mostrano i risultati delle misure effettuate sulle deboli righe d'assorbimento overtone che si collocano attorno a 12670 cm^-1 (790 nm) misurandone la posizione con un errore massimo di 0.01 cm^-1 (potere risolutivo dello spettrometro ~10⁷) prendendo come riferimento le righe d'assorbimento dello iodio molecolare. Vengono date le classificazioni rotazionali fino a J = 40 e ricavati i relativi parametri roto-vibrazionali.

The European Physical Journal D, Vol. 47(1), 1–5 (2008)

Light-induced sodium desorption from paraffin

A. Lucchesini, S. Gozzini
Istituto per i Processi Chimico-Fisici del CNR, Area della Ricerca di Pisa, Italy

L. Marmugi, and G. Postorino
Dipartimento di Fisica dell'Università degli Studi di Pisa, Italy

Abstract

Sodium photoejection from a paraffin coated cell has been observed and analyzed in detail. The effect has been detected by observing the fluorescence induced by a cw dye laser. A maximum Na density of about 3.8 x 10⁸ atoms/cm³ was obtained by shining the cell with 1 W Ar⁺ laser green light. A progressive slowing of the dynamics of the process is reported, probably due to a change in the chemical rearrangement of the Na atoms in the coating under intense light exposure. This aging effect represents a limitatìon in the practical application of ths kind of materials.

PACS: 42.70.Jk Polymers and organics — 68.60.-p Physical properties of thin films, nonelectronic — 68.43.Tj Photon stimulated desorption

17 references

Opt. Commun. Vol. 282(17), 3493–3498 (2009)

Diode laser spectroscopy of ammonia at 760 nm

A. Lucchesini, S. Gozzini
Istituto per i Processi Chimico-Fisici del CNR, Area della Ricerca di Pisa, Italy

Abstract

A tunable diode laser spectrometer has been employed to examine the unknown overtone absorption lines of NH₃ around 13100 cm^-1 (760 nm). The spectrometer sources are commercially available heterostructure AlGaAs tunable diode lasers operating in the "free-running" mode. The detection of the lines has been possible by the use of the wavelength modulation spectroscopy and the second harmonic detection technique. A special algorithm has been used in order to fit the highly modulated absorption lines. The weakest observed resonances have absorption cross sections on the order of 1 x 10^-25cm²/molecule or ~0.3 km^-1/amagat. For some of the more intense lines self-, air-, N₂-, He- and H₂-broadening coefficients have been obtained at room temperature and also some shifting coefficients have been measured.

Key words: Ammonia, Line broadening and shift, Overtone bands, Tunable diode laser

PACS: 33.70.Jg, 33.20.Kf, 07.60.Rd, 42.55.Px

36 references

Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 112(9), 1438–1442 (2011)

Diode laser spectroscopy of ethylene overtones at 830 nm

A. Lucchesini, S. Gozzini
INO - CNR - U.O.S. di Pisa, Area della Ricerca, Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

A tunable diode laser spectrometer has been employed to examine the 3rd overtone absorption lines of C₂H₄ at around 12000 cm^-1 (830 nm). The spectrometer sources are heterostructure AlGaAs tunable diode lasers operating "free-running". By the aid of the wavelength modulation spectroscopy with the second harmonic detection technique and a Herriott type multipass cell 63 very weak absorption lines have been observed for the first time, with cross sections as low as 2x10^-26 cm²/molecule, equivalent to ~0.05 km^-1/amagat. The self-broadening coefficient has been measured for one of the most intense lines.

Keywords: Ethylene, Overtone bands, Line and band widths, Tunable diode laser

12 references

Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 130, 352–358 (2013)

Diode laser spectroscopy of methyl fluoride overtones at 850 nm

A. Lucchesini, S. Gozzini
INO - CNR - U.O.S. di Pisa, Area della Ricerca, Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

156 ¹²CH₃F overtone absorption lines, comprised between 11545 and 11836 cm^-1, have been observed by using a tunable diode laser (TDL) spectrometer. Their intensities range around 10^-26 cm/molecule and have been measured by utilizing commercial AlGaAs/GaAs laser diodes through the wavelength modulation (WM) and the 2nd harmonic (2ƒ) detection techniques. Self-broadening coefficients and line strengths have been measured at room temperature for seven of the strongest transitions, while air-broadening coefficients have been obtained for two lines. In addition, self- and air-collisional shifts have been measured for the 11564.25 cm^-1 transition.

Keywords: Methyl fluoride, Overtone bands, Line and band widths, Tunable diode laser, Symmetric top molecule

26 references

(italian)

Atti del 100° Congresso Nazionale della Società Italiana di Fisica - Pisa, 22-26 Settembre 2014, p. 73

Spettroscopia overtone delle molecole CH₃F e CH₃Cl a 850-860 nm

A. Luchesini, S. Gozzini
Istituto Nazionale di Ottica del Consiglio Nazionale delle Ricerche - Area della Ricerca di Pisa

Riassunto

Centinaia di deboli righe d’assorbimento roto-vibrazionali overtone delle molecole symmetric top CH₃F e CH₃Cl sono state osservate per la prima volta per mezzo della tecnica spettroscopica a diodi laser a modulazione di frequenza con rivelazione in fase. Tali righe di interesse atmosferico ed astrofisico hanno intensità dell’ordine di 10^-26 cm/molecola e coefficienti d’estinzione dell’ordine delle decine di km/amagat, per cui è stato necessario utilizzare cammini ottici di decine di metri con celle di misura multipasso alla Herriott. Per alcune di esse sono stati misurati anche i coefficienti di allargamento e shift collisionali.

Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 168, 170–175 (2016)

Diode laser spectroscopy of methyl chloride overtones at 850–860 nm

A. Lucchesini, S. Gozzini
INO - CNR - U.O.S. "Adriano Gozzini", Area della Ricerca, Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

By using a tunable diode laser (TDL) spectrometer 156 CH₃Cl overtone absorption lines have been detected in the range between 11590 and 11760 cm^-1 (8500 – 8625 Å). Their strengths range around 10^-26 – 10^-27 cm/molecule and have been measured by utilizing commercial AlGaAs/GaAs laser diodes through the wavelength modulation spectroscopy (WMS) and the 2nd harmonic (2ƒ) detection techniques. For one line the self-broadening coefficient has been obtained.

Keywords: Methyl cloride, Overtone bands, Line and band widths, Tunable diode laser, Symmetric top molecule

18 references

Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 283, 108140 (2022)

Nitrous oxide spectroscopy at 887 nm

A. Lucchesini, J. González-Rivera
INO - CNR - S.S. "Adriano Gozzini", Area della Ricerca, Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

Using a tunable diode laser spectrometer 53 ¹⁴N₂¹⁶O overtone absorption lines have been detected in the range between 11,233 and 11,283 cm^-1 (886-890 nm), with estimated strengths ranging around 10^-27 – 10^-28 cm/molecule. 9 new lines have been found. They have been measured by utilizing commercial AlGaAs/GaAs laser diodes through the wavelength modulation spectroscopy and the 2nd harmonic detection techniques. Self-broadening coefficients have been obtained for 13 of these lines for the first time. Refined molecular parameters have been achieved for this overtone band.

Keywords: Nitrous oxide, Overtone bands, Line lists, Line and band widths, Tunable diode laser

15 references

Spectroscopy Journal, Vol. 1, Issue 1, 28–36 (2023)

Diode laser overtone spectroscopy of methyl iodide at 850 nm

A. Lucchesini
INO - CNR - S.S. "Adriano Gozzini", Area della Ricerca, Via G. Moruzzi 1, 56124, Pisa, Italy

Abstract

Using Tunable Diode Laser Absorption Spectroscopy (TDLAS), 82 CH₃I overtone absorption lines were detected for the first time in the range between 11,660 and 11,840 cm-1 (844–857 nm),with strengths estimated around 10^-27 – 10^-26 cm/molecule. The lines were measured utilizing commercial heterostructure F–P type diode lasers, multipass cells, and wavelength modulation spectroscopy with the second harmonic detection technique. A high modulation amplitude approach was adopted for the analysis of the line shapes. Self-broadening coefficients were obtained for two lines.},

Keywords: Methyl iodide, Overtone band, High-resolution spectroscopy, Tunable diode laser, Line shape and width

21 references