Regenerative oscillations

Bade P, Bourvier M and Coe J S 1987 Nd YLF mode-locked oscillator and regenerative amplifier Opt. Lett. 12 319-21... 

Examples of such situations are very numerous perhaps the best known example is the transition of the performance of an electronic circuit from regenerative amplification to the generation of oscillations. The parameter A in this case is the coefficient of mutual inductance between the anode and the grid circuits. As long as A < A0, the circuit functions as amplifier whose coefficient of amplification gradually... 

This particular bifurcation exists in the example from electronics mentioned above the regenerative amplifier has as its phase portrait SUS and after the bifurcation it becomes simply US, that is, an ordinary oscillator. 

The laser system consisted of a home-built Ti sapphire fs laser oscillator and regenerative amplifier (RGA). The pulse duration was 50 fs at 800 nm and 1 kHz repetition rate. The output of the RGA was split into two parts. One part was used as pump pulse. The other part served as a source for the generation of probe pulses with the help of a non-collinear optical parametric amplifier (NOPA, Clark). The sample preparation was explained elsewhere [7]. Briefly, sodium (Alfa Aesar) was used as received and sodium bromide (Alfa Aesar) was dried and re-crystallized under vacuum. The preparation of the samples was carried out in a glovebox under argon atmosphere. Localized electrons were generated by heating the metal-salt mixture to 800 °C, i.e. well above the melting point of the salt. 

Fig. 14.6. Three-dimensional view of the Teramobile. (L) Laser system Ti Sa oscillator and its Nd YAG pump laser LI), stretcher (L2), regenerative amplifier, multipass preamplifier (L3) and their Nd YAG pump laser (LJ,) Multipass main amplifier (L5) pumped by two Nd YAG units (L6) Compressor (L7). (5), Beam expanding system (C), Power supplies D), Lidar detection system [14]...

Figure 6 Block diagram of the two-color optical parametric amplifier (OPA) and IR-Raman apparatus. CPA = Chirped pulse amplification system Fs OSC = femtosecond Ti sapphire oscillator Stretch = pulse stretcher Regen = regenerative pulse amplifier SHGYAG = intracavity frequency-doubled Q-switched Nd YAG laser YAG = diode-pumped, single longitudinal mode, Q-switched Nd YAG laser KTA = potassium titanyl arsenate crystals BBO = /J-barium borate crystal PMT = photomultiplier tube HNF = holographic notch filter IF = narrow-band interference filter CCD = charge-coupled device optical array detector. (From Ref. 96.)...

Figure S> Schemaiic layout of an ultrafasl puaip-probe spectrometer. Top left panel A cw diode-pumped, Frequency-doubled, Nd YAO laser B mode-locked Ti-S oscillator C regenerative Ti-S amplilier D Q-switched, frequency-doubled Nd YLF amplifier pump laser E second/third-iiarmonic generators or OPA. Lower right panel F continuum generation G sample H CCD spectrograph. The double arrow indicates the optical delay stage, and the dashed tine indicates the pump-beam trajectory.

Figure 6. Schematics of the three common regenerative cryocoolers. The Stirling eryocooler (a) uses a valveless compressor or pressure oscillator and has a moving displacer operating synchronously with the piston. The pulse tube eryocooler (b) has no displacer in the cold head. The Gifford-McMahon eryocooler (c) uses a valved compressor with oil lubrication and oil removal equipment.

The aspect of regenerative cryocoolers of interest here is their miniaturization, possibly for use in MEMS devices. The largest component of regenerative cryocoolers is the compressor, or pressure oscillator. The mechanical power, or PV power, output from the pressure oscillator is given by... 

Transient spectroscopy experiments were performed with a pump-probe spectrometer [7] based on a home-made original femtosecond Ti saphire pulsed oscillator and a regenerative amplifier system operated at 10 Hz repetition rate. The Tirsaphire master oscillator was synchronously pumped with doubled output of feedback controlled mode-locked picosecond pulsed Nd YAG laser. The pulse width and energy of Ti saphire system after the amplifier were ca. 150 fs and 0.5 mJ, respectively, tunable over the spectral range of 760-820 nm. The fundamental output of the Ti saphire system (790 nm output wavelength was set for present study) splitted into two beams in the ratio 1 4. The more intense beam passed through a controlled delay line and was utilized for sample... 

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