Stabilization of a CO2 pump laser using external CH3OH stark-cell modulation

Powerful Optically Pumped Far-Infrared Laser with Stable Output Power

“…The signals related to physical phenomena such as the photo-galvanic effect, 7,8) the photo-acoustic effect, 9,10) the Stark Lamb dip (SLD) absorption, [11][12][13] Lamb dip absorption, 14,15) interferometry in stabilized cavities, 16) and the transferred Lamb dip (TLD) absorption 17) can be applied to measure the frequency stability of the CO 2 lasers. We examined these methods and adopted the method using SLD absorption because of the simplicity of the apparatuses and the sharpness of the absorption signals.…”

“…Required frequency resolution for the application 6) of our CO 2 laser is in the range of a few hundreds of kHz. The reported frequency stabilities for the SLD effect, [11][12][13] are about 5 × 10 −9 and corresponding frequencies are about 150 kHz. So we conclude this method is sufficient for the requirement of our experiments.…”

“…A one-way configuration, 11,12) where the detector is placed in position A in Fig. 1(a), becomes a two-way configuration when the detector is placed in position B.…”

Stabilization of 48- and 57-&#x00B5;m CH<inf>3</inf>OD lasers pumped by 9R(8) CO<inf>2</inf> laser for two color interferometer

“…For high density operation of the LHD, powerful and stable FIR lasers with different wavelength at 40 to 70 μm are required to measure the vibration compensated electron density profiles. So we have been developing a two color interferometer using simultaneously oscillated 48-and 57-μm CH 3 OD lasers pumped by 9R(8) CO 2 laser 2 . In order to apply the FIR lasers to the interferometer, high stability of the frequency and power are required.…”

“…The fluctuation of the FIR laser output power is strongly dependent on the fluctuation of the pump CO 2 laser frequency. We have examined the frequency stabilization of the 9R(8) CO 2 laser by an external Stark-cell modulation method 3 . This method has advantages that can be stabilized at the optional frequency in the free spectral range and does not require the internal frequency modulation of the CO 2 laser.…”