Intracavity Bragg grating

Experimental investigation of intracavity Bragg gratings

“…The shape of the ref lection diffraction peak was described mainly by the Fabry -Perot transmission, since only light coupled to the cavity could be diffracted by the Bragg grating. As expected from plane-wave calculations, 5 the angular width of r DR was strongly reduced (by roughly a factor of 7) compared with the corresponding theoretical results for the bare sample. Moreover, the absolute maximum diffraction efficiency was ϳ4 3 10 22 , i.e., 220 times higher than that of the bare Bragg sample with the same thickness and index modulation.…”

“…3,4 Recent calculations have shown that the diffraction properties of transmission Bragg gratings are greatly improved when the indexmodulated medium is embedded in a Fabry -Perot resonator. 5 Specifically, intracavity Bragg gratings can give very high diffraction eff iciencies and angular selectivities, even in the case of thin materials or low index-modulation amplitude, which is crucial in optical signal processing. When the Bragg condition and Fabry -Perot resonance are simultaneously fulf illed, the performance of the intracavity device is greatly enhanced, in comparison with that of a bare sample.…”

Diffraction of Gaussian beams on intracavity Bragg gratings

“…1,2 However, because of the low refractive-index modulations or the small thicknesses of the nonlinear material used for recording these gratings, the Bragg diffraction properties of thick gratings may be insufficient for practical applications. In such a case, as shown theoretically, 3 this inconvenience can be overcome by placing the sinusoidal grating in a FabryPerot cavity. More recently, and with an eye toward the design of practical devices, the Bragg criterion for such intracavity gratings 4 and the influence of intracavity losses or amplification 5 have been theoretically studied.…”

“…This leads us to reconsider the planewave approximation of Ref. 3. Gaussian beams have been extensively studied 7,8 to account for the properties of such devices as Fabry-Perot cavities 9,10 or diffraction gratings 11,12 illuminated by small diameter laser beams.…”

Efficient Bragg-like operation of intracavity low-efficiency plane gratings

“…It has been shown that inserting a volume grating in a Fabry-Perot resonator is a good means of improving its efficiency, especially if the volume grating fills the cavity entirely. 5 In that case, the thickness threshold toward the Bragg regime can be significantly lowered 6 because of the multiple paths in the nonlinear medium, but many efficient nonlinear media are available only in such small thicknesses that no Bragg regime can be obtained in this way.…”