Dye laser oscillator-amplifier system

R. Wallenstein, T.W. Hansch Powerful dye laser oscillator-amplifier system for high-resolution spectroscopy. Opt. Commun. 14, 353 (1975)... 

Fig.7 18. Pressure-tuned dye laser oscillator-amplifier system. The ex-ternal confocal F.P.I. serves as narrow band spectral filter. The two amplifiers are pumped by the same N2 laser [7.40]...

The CARS system used to measure temperature and species concentrations in the combustor zone is composed of a single-mode ruby-laser oscillator-amplifier with a repetition rate of 1 Hz and a ruby-pumped, near-infrared broad-band dye laser. The two laser beams are combined collinearly and focused first into a cell containing a nonresonant reference gas and then into the sample volume (approximately 30-u diam. x 2 cm) in the combustion region. The anti-Stokes beams produced in the sample and reference volumes are directed to spatially separated foci on the entrance slit of a spectrometer and detected by separate photomultiplier tubes. An optional means of detection is provided for the sample signal in the form of an optical multichannel analyzer (OMA), which makes it possible to obtain single-pulse CARS spectra. 

In order to achieve a reasonable signal strength from the nonlinear response of approximately one atomic monolayer at an interface, a laser source with high peak power is generally required. Conuuon sources include Q-switched ( 10 ns pulsewidth) and mode-locked ( 100 ps) Nd YAG lasers, and mode-locked ( 10 fs-1 ps) Ti sapphire lasers. Broadly tunable sources have traditionally been based on dye lasers. More recently, optical parametric oscillator/amplifier (OPO/OPA) systems are coming into widespread use for tunable sources of both visible and infrared radiation. 

These limitations have recently been eliminated using solid-state sources of femtosecond pulses. Most of the femtosecond dye laser teclmology that was in wide use in the late 1980s [11] has been rendered obsolete by tliree teclmical developments the self-mode-locked Ti-sapphire oscillator [23, 24, 25, 26 and 27], the chirped-pulse, solid-state amplifier (CPA) [28, 29, 30 and 31], and the non-collinearly pumped optical parametric amplifier (OPA) [32, 33 and 34]- Moreover, although a number of investigators still construct home-built systems with narrowly chosen capabilities, it is now possible to obtain versatile, nearly state-of-the-art apparatus of the type described below Ifom commercial sources. Just as home-built NMR spectrometers capable of multidimensional or solid-state spectroscopies were still being home built in the late 1970s and now are almost exclusively based on commercially prepared apparatus, it is reasonable to expect that ultrafast spectroscopy in the next decade will be conducted almost exclusively with apparatus ifom conmiercial sources based around entirely solid-state systems. 

Laser I A femtosecond dye laser system composed of a femtosecond oscillator and an amplifier, generating tunable (550-640 nm) pulses in 10-Hz and 400-fs fwhm. 

Fig.11.15. Cavity-dumped synchroneously-pumped dye laser system with synchronization electronics [Courtesy Spectra Physics] (a) Experimental setup (p.d. pulse delay, f.d. frequency divider, ph.o. phase-locked oscillator. A amplifier), (b) Correct synchronization of a mode-locked laser pulse with the time of maximum output coupling of the cavity dumping pulse...

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