Fast frequency stabilization of a cw dye laser

Abstract

A system is described for stabilizing a cw dye laser frequency to a high-finesse optical cavity. The length of this optical cavity is locked to a CH4-stabilized He-Ne laser with a tunable frequency-offset technique. A very fast servo system using an intracavity KD*P crystal), a long dye laser cavity, and the stabilized optical cavity result in an absolute frequency stability of 1 kHz for an integration time of 10−4 sec and 300 Hz for 300 sec. Intensity is stabilized to one part in 104.

A servo controlled electro-optic modulator for cw laser power stabilization and control

“…With the electro-optical crystals now commercially available it is possible to build a simple low cost system to extra-cavity stabilize the output of many cw lasers to better than .05% for stabilization bandwidths of DC to 100 kHz. [1,2,3]^The systems currently employed at NBS to stabilize the laser beam power used for high accuracy characterization of detectors are described.…”

A frequency stabilized CW dye laser for spectroscopic and metrological applications

“…However, the subsequent huge amount of work performed in this direction in many laboratories has revealed the numerous difficulties to be solved [2]. Sources suitable for sub-Doppler atomic spectroscopy, where one is dealing with linewidths of some 10 MHz, are now readily obtained but the much narrower sources needed for molecular spectroscopy and metrological applications are only beginning to become available [3,4]. In this paper we describe a dye laser to which several servo loops confer a linewidth of 5 parts in 1010 (250 kHz FWHM), a frequency stability of 1.5 part in 1012 over 100 s and an amplitude stability better than one part in 104.…”

“…In order to obtain a high short and long term frequency stability together with some tunability of the laser, it is necessary to use three successive servo loops [3,4,5] whose principle is depicted in figure 1. The first, acting on the cavity output mirror pzt, locks the dye laser frequency to the side of the transmission curve of an external reference cavity.…”

“…The joint action of the two above mentioned servo loops results in transferring to the dye laser the very high short term frequency stability of the transfer oscillator. Finally, the remaining long term drifts are eliminated by a third servo loop which locks, with a variable frequency interval, the frequency of the transfer oscillator to the output of an I2 -stabilized H~-Ne standard via a frequency offset locking technique [3][4][5][6]. The best way to evaluate the frequency stability of such a source would be to study the beat note between it and a similar unit or, even better, an optical frequency standard.…”

“…For spectroscopic studies of weak and narrow transitions, a good amplitude stability is also required. An electrooptic amplitude corrector [7,3] is used for this purpose, giving an amplitude stability exceeding one part in 104.…”