Optimized quantization for diffractive phase elements by use of uneven phase levels.

Many applications of diffractive phase elements involve the calculation of a continuous phase profile, which is subsequently quantized for fabrication. The quantization process maps the continuous range of phase values to a limited number of discrete steps. We present a new scheme with unevenly spaced levels for the design of diffractive elements and apply it to the design of intracavity mode-selecting elements. We show that this modified quantization can produce significantly better results than are possible with a regular or even the bias-phase-optimized quantization scheme that we reported here earlier. In principle this process can be employed to a greater or lesser extent in any quantization process, allowing the fabrication of diffractive elements with much improved performance.

Optimized phase quantization for diffractive elements by use of a bias phase.

Many applications of diffractive phase elements involve the calculation of a continuous phase profile that is subsequently quantized for fabrication. The quantization process maps the continuous range of phase values to a limited number of discrete steps. We report our observation of the influence of this quantization process on the performance of mode-selecting diffractive elements and show that the quantization process produces significantly better results by use of an optimized bias phase. In principle this process can be employed to a greater or lesser extent in any quantization process.

Regenerative ring-laser design by use of an intracavity diffractive mode-selecting element.

We report what we believe to be the first application of diffractive phase elements for transverse mode selection in laser ring resonators. We show that this resonator type offers several advantages over Fabry-Pérot resonators with diffractive mirrors. The design for a regenerative ring resonator that produces an eighth-order super-Gaussian intensity profile beam is presented. Numerical simulations, including modeling of the gain saturation and experimental tests, have been carried out to demonstrate the performance of this approach for cw and pulsed operations.