Computer control of broadly tunable lasers: conversion of a color center laser into a high resolution laser spectrometer

Abstract

The conversion of a commercial color center laser (Burleigh FCL-20) into a computer-controlled high resolution laser spectrometer is described. The techniques and methods developed are generally useful for the control of any broadly tunable cw laser. Superposition of several kinds of computer-controlled feedback upon a table look-up (feed-forward) procedure is used for each of the control elements. This feedback removes the coupling between the tuning elements and eliminates the effects of the nonideal properties of the control elements such as PZT hysteresis and creep. The resulting spectrometer is capable of acquiring high resolution (instrumentally limited by free running laser jitter to ~3 MHz) spectra which can be precisely measured (~0.0003 cm(-1)). The spectrometer has routinely made continuous single-mode scans of 30,000 points separated by 10 MHz covering 10 cm(-1).

The ν1 + ν5 Band of HCCN: Determination of the ν5 Vibrational Energy

“…The total pressure in the cell was maintained at 7.2 Torr. The transient infrared absorption spectrum of HCCN was probed using a computer-controlled color center laser, Burleigh FCL-20 (17), with Li-doped RbCl crystal operating from 2.7 to 3.3 m and pumped by an all-lines krypton ion laser (0.7 W). Spectral data were collected using a balanced detector technique (two liquid-nitrogen-cooled InSb detectors) to reduce the substantial noise from the color center laser.…”

Survey of H3+ Transitions between 3000 and 4200 cm−1

“…A number of groups have done this in the past (28)(29)(30)(31)33), and our system is modeled after the Princeton apparatus (33). Two analog outputs (National Instruments Model PCI-MIO-16E-4) are amplified (Burleigh RC-44 and RC-45) and sent to the piezo translators (PZTs) attached H + 3 TRANSITIONS, 3000-4200 cm −1 53 to a cavity folding mirror and one of the internalétalon plates.…”

“…To minimize mode hopping during scanning or PZT rachet-backs, an error signal is produced by applying a small 1-kHz dither to theétalon PZT as discussed in Ref. (28). This error signal is fed back into the computer and is used to adjust the alignment of theétalon mode to the cavity mode.…”

High-power CW single-frequency Nd:YVO4/LBO laser quasi-continuously tuneable over a wide frequency range

“…Spectral values of sub-range terminal points cannot be matched better than to the precision of the laser's output linewidth, therefore sub-range stitching to this precision is the best attainable. This type of spectral stitching was done in many systems [11][12] with the help of a high-precision radiation wavelength meter, whereas in the present report, it is performed by means of a high-finesse scanning confocal interferometer. We have also for the first time applied the method of quasi-continuous laser output frequency tuning to a powerful diodepumped solid-state laser.…”