Phase conjugation

About: Phase conjugation is a research topic. Over the lifetime, 3694 publications have been published within this topic receiving 49099 citations.

Self-pumped phase conjugation of 18°-cut Ce-doped KNSBN crystal at 632.8 nm

Abstract: We report the self-pumped phase conjugation of an 18°-cut Ce-doped (KyNa1−y)2m(SrxBa1−x)1−m Nb2O6 crystal at a 632.8-nm He–Ne laser wavelength. A maximum phase-conjugation reflectivity of 84.3% has been measured. In addition, its incident angular response and time response are measured.

Multiline phase conjugation at 4 microm in germanium.

Abstract: Phase conjugation by degenerate four-wave mixing in the 4-μm region in germanium has been observed for both single-line and multiline radiation. By using single-line output of a DF laser at 3.8 μm, χ3 has been measured to be 4 × 10−11 esu. Phase conjugation of multiline laser output has been achieved with an efficiency of 0.03%, a level that is consistent with the susceptibility found for single-line phase conjugation and the assumption of independent conjugation of each line of the multiline output.

Polarization independent, all-fiber phase conjugation incorporating inline fiber DFB lasers

Abstract: We propose and demonstrate a novel technique for optical wavelength conversion and phase conjugation by fiber four-wave mixing using inline fiber distributed-feedback lasers as orthogonally polarized pump sources. This technique features polarization independent operation and a simple all-fiber configuration without the need for externally injected pumps. Polarization dependency as low as 0.5 dB has been achieved using this technique.

Self Pumped Optical Phase Conjugation at 1.06 μm in Te-doped Sn 2 P 2 S 6

Abstract: We demonstrate self-pumped optical phase conjugation in Te-doped Sn2P2S6, a semiconducting ferroelectric crystal, using a 1.06 μm wavelength cw Nd:YAG laser. The photorefractive gain of this crystal has been increased to Γ = (3.9 ± 0.4)cm-1 by Te doping. We observed self-pumped optical phase conjugation in a ring cavity scheme with phase conjugate reflectivities of more than 40 percent and a very fast phase conjugate rise time below 100ms at a light intensity of 20 W/cm2. This is more than two orders of magnitude faster than in any other photorefractive crystal, as e.g. in Rh-doped BaTiO3.

Retroreflective array as resonator mirror.

Abstract: It was pointed out recently that an array of corner reflec­ tors acts as an approximate phase conjugator. Phase conju­ gation is made approximately not only because of the finite size of the conjugating elements, but also because of the in­ version suffered by each plane wave. Orlov et al. demon­ strated that such an array can correct the dynamic index profile in optically pumped neodymiumrglass rod amplifiers. Here we demonstrate that a retroreflective array of corner cubes can be used as a mirror to compensate for distorting elements inside a laser resonator. The retroreflective arrays used in our experiment were the common plastic retroreflectors used on automobiles, bicycles, and highway signs. They are plastic replicates forming an array of 2.5-mm diam corner cubes, commercially available in clear, yellow, or red. Their absorption is strong (even the clear one) in the infrared. We solved that problem by copper coating the backside of the reflectors, which forms an identical array of corner cubes. These arrays are of the incoherent type in the terminology of Ref. 1. The first experiment was made with a (2 × 2-cm) TEA CO2 laser (Tachisto 215). The optical resonator was formed by a 36% reflecting flat mirror and by the retroreflective array located 1 m away. The alignment of such a resonator is not critical; for example, to stop laser action one has to tilt the retroreflector by as much as 25°. A burn spot of the output is shown in Fig. 1. The grain structure shown is reproducible from shot to shot for a given orientation of the retrore­ flector.