Frequency stabilization of a Ho:Tm:YLF laser to absorption lines of carbon dioxide

Koch, Grady J.; Dharamsi, A. N.; Fitzgerald, Colleen M.; McCarthy, Jean

doi:10.1364/ao.39.003664

Cited by 60 publications

(28 citation statements)

References 10 publications

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“…For pure laser wavelength modulation (WM), the odd derivatives cross zero at the centre of the absorption line and vary linearly around this point, so that they can act as an error signal in a servo loop. The application of WMS to the stabilisation of a laser source on water-vapour lines in the near infrared has been demonstrated [20][21][22][23], but generally only for a single stabilised laser. The same basic principle was applied in this work for the stabilisation of the three water lines, but its practical implementation differed slightly due to the different strengths of the absorption lines and to the influence of the residual intensity modulation (IM) of the laser.…”

Section: On-line Lockingmentioning

confidence: 99%

Diode laser frequency stabilisation for water-vapour differential absorption sensing

et al. 2006

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We describe a low-power continuous-wave laser system for water-vapour sensing applications in the 935-nm region. The system is based on extended-cavity diode lasers and distributed-feedback lasers and delivers four single-mode frequency-stabilised optical signals. Three lasers are locked to three water-vapour absorption lines of different strengths, whereas the fourth lies outside any absorption line. On-line stabilisation is performed by wavelength-modulation spectroscopy using compact water-vapour reference cells. An offset-locking technique implemented around an electrical filter is applied for the stabilisation of the off-line slave laser to an on-line master laser at a frequency detuning of 18.8 GHz. Stabilities in the order of 15 MHz over one day were observed for the strongest lines, at the detection limit of the measurement instrumentation. The developed techniques and schemes can be applied to other wavelength ranges and molecular species. Differential absorption lidar instrumentation can in particular benefit from such a system when the stabilised lasers serve as injection seeders to pulsed power oscillators.PACS 42.62.Fi; 42.68.Wt IntroductionWater vapour is a key component in the atmosphere. As part of the global water cycle it strongly influences the surface/atmosphere interaction processes. Its phase transitions determine the transport and redistribution of energy around the globe, affecting the weather. It plays a part in many atmospheric chemistry processes and, as a major greenhouse gas, plays a central role in the climate. Improved water-vapour measurements are needed in numerous disciplines and scientific issues [1]. For meteorology, weather forecasting, climatology as well as atmospheric process studies, it is important to accurately monitor both the temporally and spatially variable water-vapour concentration, not only through point or integrated column measurements, but also with a high spatial and temporal resolution.The water-vapour differential absorption lidar (DIAL) technique provides an independent and direct manner to retrieve the atmospheric humidity profile in a continuous way, u Fax: +41-32-722-04-20, E-mail: renaud.matthey@ne.ch with a high temporal and spatial resolution [2][3][4]. It is based on the comparison of the lidar signals at two wavelengths, one coinciding with a water-vapour absorption line of adequate strength and the second sufficiently far away from any line not to undergo substantial absorption. The quality of the data obtained from ground-based [5,6] and airborne [7][8][9][10] instruments in terms of vertical resolution, precision and accuracy indicates the feasibility of a space-borne instrument [11], from which major advances in humidity profiling with global coverage are expected [12]. While ground-based water-vapour DIALs operate at two wavelengths only (one on-line and the other off-line), space-borne instruments may operate at a set of different on-line wavelengths corresponding to absorption lines of different strengths, thus providing different p...

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Section: On-line Lockingmentioning

confidence: 99%

Diode laser frequency stabilisation for water-vapour differential absorption sensing

et al. 2006

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“…Several steps towards such a multi-use lidar application have already been accomplished. Frequency control and locking of the laser wavelength to the CO 2 absorption line has been demonstrated [8][9][10]. Double pulse operation of the 2-micron laser has been accomplished, which extracts more optical energy from the laser, thus raising efficiency, and opening the possibility of obtaining both DIAL laser wavelengths from each laser firing [11].…”

Section: Pulsed Lasermentioning

confidence: 99%

Laser and lidar technologies for Earth and planetary remote sensing applications

Singh

Kavaya

2005

SPIE Proceedings

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“…First, all pixels less than 20% of the peak Ivoltagel pixel are discarded. Denoting the range-Doppler image magnitude squared voltage as "I(i,j)" and the frequency bins by "F(i,j)," we then employ: 1) Mean Doppler fM = I(i, j)x F(i, j) / I(i, j) (14) 2) Median Doppler fMed =Median{F(i,j)} (15) 3) Average Doppler fA8 = F(i, j) / size(F(i, j)) Doppler spread is set to zero to model several glint returns. Note two speckle maxima and weak side lobes.…”

Section: Preliminary Rrdi Image Features Examinedmentioning

confidence: 99%

<title>Cylindrical target Doppler and Doppler-spread feature estimation using coherant mode-locked pulse laser radars with long observation times</title>

Youmans¹

2001

SPIE Proceedings

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Mode-locked solid-state-laser coherent laser radars operating continuously and at short wavelengths are capable of forming range-resolved Doppler and intensity images of distant spinning objects. The continuous mode-locked repetitive pulse operation allows demonstrated long laser coherence-lengths to achieve efficient heterodyne detection. The continuous repetitive pulsed operation also allows one to probe an object for arbitrarily long observation times resulting in precise center-of-mass-Doppler estimation and micro-Doppler vibration and spin measurements, as well as the temporal integration of the received signals to increase effective signal strength. We investigate this ladar waveform for imaging spinning cylinders at large distances, so that there is on the order of two detected photons approximately every 1 ,000 micro-pulses (-27dB CNR) and applying simple estimators to the Doppler center-of-mass and Doppler-width for automatic target recognition purposes. A simple preliminary model for "reflective" cylinders is also presented.

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Frequency stabilization of a Ho:Tm:YLF laser to absorption lines of carbon dioxide

Cited by 60 publications

References 10 publications

Diode laser frequency stabilisation for water-vapour differential absorption sensing

Diode laser frequency stabilisation for water-vapour differential absorption sensing

Laser and lidar technologies for Earth and planetary remote sensing applications

<title>Cylindrical target Doppler and Doppler-spread feature estimation using coherant mode-locked pulse laser radars with long observation times</title>

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