Optical parametric oscillator pumping

A conceptually even simpler approach uses just one optical parametric oscillator, pumped by a dye laser or diode laser at 4f and oscillating at the two frequencies f and 3f. The signal frequency f is enforced by injection locking with light from the 3.39 pm reference laser. The pump frequency is adjusted so that the idler frequency agrees with the third harmonic of the reference laser. The seventh harmonic is then generated by simply summing idler and pump frequency. 

Fig. 5.120. Temperature tuning curves of signal and idler wavelengths for a LiNb03 optical parametric oscillator pumped by different pump wavelengths [5.292]...

Figure 3 Schematic representation of a singly-resonant optical parametric oscillator. Pump wave of frequency cop, (reflected) signal wave of frequency os, idler wave of frequency a>. The signal wave (Os becomes amplified. 6p denotes the angle of orientation of the direction of propagation with respect to the crystal optic axis. Adapted with permission from Tang CL and Cheng LK (1995) Fundamentals of Optical Parametric Processes and Oscillators. Amsterdam Harwood Academic Publishers.

The OPA should not be confiised with an optical parametric oscillator (OPO), a resonant-cavity parametric device that is syncln-onously pumped by a femtosecond, mode-locked oscillator. 14 fs pulses, tunable over much of the visible regime, have been obtained by Hache and co-workers [49, with a BBO OPO pumped by a self-mode-locked Ti-sapphire oscillator. 

It is well known that by inserting an optical amplifier obtained by population inversion in an optical cavity, one can realize sources of coherent radiations, namely lasers. One can operate in the same way with parametric amphfication as shown on Fig. 1. A nonlinear crystal illuminated by an input pump is inserted in an optical cavity. This cavity is represented for convenience as a ring cavity but consists usually of a linear cavity. An important difference with the laser is that there are three different fields, insfead of one, which are presenf in the amplifying medium, all these fields being able to be recycled by the cavity mirrors. One obtain thus different types of "Optical Parametric Oscillators" or OPOs. 

We have shown the different aspects of Optical Parametric Oscillators which explain the present interest for these sources, in fundamental as well as in applied physics. The very rapid development of compact, not power demanding sources including the pump laser and the OPO, should lead to an even wider use of such sources, in particular for industrial or medical applications. 

The dissociation laser light between 230 and 305 nm was produced by frequency doubling the output of an optical parametric oscillator (Spectra-Physics MOPO-730) pumped by an injection-seeded Nd YAG... 

A useful source of continuously tunable radiation from the near UV to the near-IR with unexplored potential in fluorescence studies is the optical parametric oscillator (OPO). These devices have been around since the 1960s(73) and have received a lot of coverage recently in laser and optoelectronic journals/74 This resurgence of interest in OPOs has been brought about by recent improvements in nonlinear crystals and the development of all-solid-state pump-laser sources with the required levels of coherence and intensity. 

The optical parametric oscillator (OPO) is based on the parametric interaction of a strong pump wave with a nonlinear medium that has a highly nonlinear susceptibility. 

Khaydarov, J. D., Andrews, J. H., and Singer, K. D. 1994. Pulse compression in a synchronously pumped optical parametric oscillator from group-velocity mismatch. Opt. Lett. 19 831-33. 

In light of these wavelength dependent effects described above, Richmond and coworkers have recently completed a more extensive wavelength dependent study of the rotational anisotropy on Ag(l 11) [136, 137], One set of experiments has involved the use of photons of lower energy in the infrared in an attempt to see if the rotational anisotropy would change as the incident and SH photons are more energetically removed from surface or bulk resonances [136]. They used the 1.53 pm output from an optical parametric oscillator which was pumped by the 1064nm output of... 

Mak, G., Fu, Q., van Driel, H.M. Externally pumped high repetition rate femtosecond infrared optical parametric oscillator, Appl. Phys. Lett. 60, 542-544 (1992)... 

Still an alternative way for tuning is to mix fix-frequency terawatt radiation (cOf) with tuneable radiation (o from an optical parametric oscillator/amplifier [29], which is pumped by a fraction of the fixed-frequency output. This is done in a pulsed rare-gas jet, where new frequency components ncOf mco are generated. Here, n normally is a large number and m a small number. Promising results have been obtained [30,31]. 

Measurements of optieal amplification were carried out in a pump and probe experimental setup. The pump radiation was provided by an optical parametric oscillator (OPO) sintonized at 975nm with high energy pulses between 50 and 115 mJ/cm. The probe beam was obtained by a lOOOW lamp, giving a signal power density of 195 pW/cm at 650 nm. 

Near Infrared. Wavelength range from about 750 nm to 3 pm. Optical Parametric Oscillator. Uses nonlinear optical effects in a crystal to split the pump beam into two coherent output beams of tuneable wavelength. The sum of the reciprocal output wavelengths is equal to the reciprocal input wavelength. 

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