Multiple-prism Beam Expanders Research Articles

Narrow linewidth, tunable dye laser by multiple-prism beam expander

12 mJ, 10-Hz green pulses from frequency doubled Nd:YAG laser was used for pumping Rhodamine 6G in a dye laser based on multiple-prism beam expander. In order to increase the stability of the output pulse, a unique dye cell with variable dimensions of active medium was designed and constructed. By using multiple-prism dispersion theory, conditions for zero-dispersion in two and four-prism beam expander configuration was calculated. In the case of two-prism configuration, tuning range of dye laser was 565–595 nm and the linewidth of pulse at 580 nm was about 1.8 nm and it is in good agreement with the calculated amount of 1.6 nm. Furthermore, using four-prism configuration tuning range of 570–585 nm was measured and the linewidth of output pulse at 575 nm was reduced up to 0.33 nm. This value may be further improved up to 0.22 nm according these calculations. In this arrangement, creation of parasitic modes, aberration in two dimensions and most of the alignment problems with the lens telescopes were resolved.

Modified Brewster telescopes: comment

The literature of multiple prism beam expanders is cited in reference to modified Brewster telescopes.

Transmission efficiency in achromatic nonorthogonal multiple-prism laser beam expanders

It is shown that nondispersive, nonorthogonal, multiple-prism beam expanders can be designed using the generalized multiple-prism dispersion formula. Further, it is shown that for the same beam-expansion coefficient, simple multiple-prism expanders, with orthogonal beam exit, can be easily designed in close form to provide greater transmission than numerically designed nonorthogonal double-prism expanders.

Ray transfer matrix analysis of multiple-sprism dye laser oscillators

A ray transfer matrix description of multiple-prism beam expanders used to produce narrow-linewidth emission in pulsed dye lasers is given. The formulae are then applied to describe beam divergence characteristics of a narrow-linewidth multiple-prism grating oscillator. A comparison between theory and measured beam divergence and laser linewidth is provided.

Single-mode flashlamp-pumped dye laser oscillators

In this paper, we report single-longitudinal-mode operation in a flashlamp-pumped dye laser incorporating a multiple-prism beam expander with the grating either in a Littrow or grazing-incidence configuration. Linewidths in the 260-MHz range were obtained, using rhodamine 590 dye at output energies exceeding 60 mJ. Pulse duration for the multiple-prism Littrow dye laser oscillator was approximately 200 ns (FWHM).

Note on achromatic multiple-prism beam expanders

It is shown that achromatic multiple-prism beam expanders can be readily designed in analytical form by direct application of the generalized solution to the n-prism dispersion problem. However, the use of the term achromatic in laser multiple-prism beam expanders, of practical interest, is questioned. Linewidth performance, in pulsed dye lasers utilizing achromatic and non-achromatic multiple-prism expanders, is discussed.

Variable linewidth high-power TEA CO_2 laser

A variable linewidth high-power TEA CO2 laser, utilizing a multiple-prism beam expander in conjunction with a Littrow-mounted grating, is described. Linewidths of approximately 250-MHz (FWHM) at a total output energy exceeding 250 mJ have been obtained at the P20 (00 degrees 1-10 degrees 0), lambda = 10.59-microm line. Laser linewidths can be varied continuously in the 250-650-MHz range for a corresponding change in output energy from 250 to 400 mJ. The present frequency selectivity method, which employs ZnSe prisms, can be applied directly to considerably higher-power CO2 lasers.

Dispersion theory of multiple-prism beam expanders for pulsed dye lasers

The single pass dispersion of multiple-prism beam expanders of interest for practical pulsed dye laser cavities is calculated. The theory is extended to enable evaluation of the overall (outward and return pass) dispersion of multiple-prism-grating combinations. It is found that although the contribution to overall dispersion from the prisms can be minimized (though not eliminated for practical expanders) by arrangement of the prisms in compensating pairs, it is in any case small (≈2%) compared to the contribution to dispersion from the grating in practical cavities. Formulae for dispersion of multiple-prism-grating combinations including up to four prisms arranged in additive or compensating configurations are given; the dispersion of an arbitrary number of prisms arranged in conjunction with a grating can also be calculated. The implications for output linewidth of pulsed dye lasers incorporating prism beam expanders are discussed.

Comparative study of beam expanders used in nitrogen laser pumed dye lasers

Four methods of beam expanding in nitrogen laser pumped dye lasers were investigated, and compared. The most important parameters of beam expanders were considered i.e. the magnification, and the efficiency of feedback. Besides the optimalization of multiple-prism beam expanders, a new combined beam expander was studied, and optimalized. This combined, prism-grating beam expander produced high efficiency of feedback in a wide range of magnifications and easily produced single mode operation with 4% energy conversion efficiency.