Dual-wavelength locking technique for coherent 2-µm differential absorption lidar applications

Abstract

A dual-wavelength locking technique for coherent 2-µm differential absorption lidar (DIAL) applications has been developed for simultaneously measuring water vapor ( H 2 O ) and radial wind velocity profiles. The two wavelengths for DIAL measurement were stabilized by sidebands of an electro-optic modulated laser, which was locked to the C O 2 R30 absorption line. We selected wavelengths of 2050.550 and 2051.103 nm to minimize the effects of height-dependent temperature and pressure variations. The long-term wavelength stability of the two locked lasers of &lt;<!-- 0.2 p m , which corresponds to 14 MHz, was achieved. The DIAL instrument using the developed technique meets the requirement of measuring the H 2 O concentration with a systematic error &lt;<!-- 5 % below an altitude of 5 km.

A 2 μm Dual-Wavelength Laser at Cryogenic Temperature with Balanced Simultaneous Emission

“…The simultaneous dual-wavelength laser (SDWL) [1] has been regarded for its applications in differential lidar [2][3][4], terahertz generation [5][6][7] and medical diagnosis [8][9][10]. The SDWL in a wavelength range around 2 µm holds great potential because of its human-eye safety and good transparency features [11][12][13].…”

A passively Q-switched dual-wavelength laser with pulsed LD coaxial end-pumped configuration

“…Dual-wavelength lasers are of great interest in wide applications such as terahertz generation, biomedicine, precision measurement and spectroscopy [1][2][3][4]. Based on the transitions between different energy levels or Stark sublevels, direct laser emission with two wavelengths from one laser crystal or two separately pumped laser crystals sharing part or the whole cavity is a conventional method for dual-wavelength generation, the latter of which is much more stable and the power ratio can be tuned by varying the pump power at the expense of a complex cavity and additional pump sources [5][6][7][8][9][10].…”

“…(1) -(3). The parameters used in simulation were: z0 = −3.3 mm, w0 = 200 μm, M 2 = 50, n1 = 1.94, n2 = 1.82, p = 100 W, l1 = 7 mm, l2 = 8 mm, N1 = 0.56×10 26 m -3 , N2 = 1.26 × 10 26 m -3 , 1 = 230 s, 2 = pump pulse with a frequency of 1 kHz and a duty cycle of 2.2% was selected to ensure the single pulse output in a single pump cycle without pulse train generation.…”

Interleaved electro-optic dual comb generation to expand bandwidth and scan rate for molecular spectroscopy and dynamics studies near 1.6 µm

“…While broadband self-referenced EO combs have been generated that cover thousands of wavenumbers with 10s of GHz comb spacings [24, 25,26], some applications benefit from the resolution agility over a few wavenumbers. For example, standoff methods for remote sensing of greenhouse gases (GHGs) in the atmosphere including differential absorption LIDAR (DIAL) [27,28] and natural target integrated path differential absorption LIDAR (IPDA) [29,30] typically require photomultipliers or avalanche photodiodes [31,32] to detect faint backscattered returns and therefore, require high power per comb tooth over bandwidths of (2-5) cm -1 and at comb resolutions from 100 MHz to 250 MHz [33]. Single quantum level studies of molecules prepared in cold environments also require (2-5) cm -1 of spectral coverage to investigate a single rovibrational [34] or rovibronic band [35,36,37] but with sub-MHz resolution.…”