Correcting Astigmatism in Diode Lasers

Short Description
Index-guided diode lasers vary in their amount of astigmatism … The longitudinal astigmatism of 10 visible-wavelength diode lasers …

Website: www.mellesgriot.com | Filesize: 56kb

Content
TO ORDER IN THE UNITED STATES CALL 1: 1-800-326-4363
OUTSIDE THE UNITED STATES, PLEASE CALL YOUR NEAREST REPRESENTATIVE
2
Correcting Astigmatism in Diode Lasers
“Knowing the problem and how to correct it is crucial to wavefront
quality.”
Astigmatism is an inherent property of the output beam of
diode lasers. In applications requiring collimation or transformation
of the diode laser’s beam, this astigmatism must be considered,
and often corrected, if the final wavefront is to approach the
diffraction limit.
Diode lasers are p-n junction devices, where radiation created by
injection of carriers across the junction is confined by a tiny optical
waveguide. This waveguide, with its plano, partially reflecting end
facets perpendicular to the junction, forms the Fabry-Perot cavity of
the diode laser.
Two general types of optical waveguides may be found in diode
lasers. The first is a dielectric slab, or index-guided, waveguide, in
which the optical energy is confined through total internal
reflection. This is achieved by surrounding the gain region with
layers of material with a lower refractive index. In a gain-guided
optical waveguide, in contrast, the energy is confined by surrounding
the optical gain region with a region of…