Electro-Optics - Applied Optics Fundamentals and Device Applications - page 79

Active region

Distributed Bragg
reflectors (DBR)

PPLN

BGO

UV

A/R-coating

Lens

GaAs substrate

Output coupler
980nm HR
490nm TR

FIGURE 2.54
This figure shows the schematics of the frequency-doubling approach to UV wavelengths. We
are working toward developing lasers with several millijoules per pulse with 1 kHz repetition
rate. (Courtesy of Princeton Optronics [PO] and Dr. Chuni Ghosh. With permission.)

Single mode
VCSEL array

Narrow divergence beam
60 mR full angle for self lasing arrays
80 mR full angle for external cavity arrays

Microlens array

FIGURE 2.55
This figure shows the architecture of collimating the individual beams from the VCSELs in
the array by means of a microlens array. (Courtesy of Princeton Optronics [PO] and Dr. Chuni
Ghosh. With permission.)

to illuminate a large area. The module has a power output 400 W and can be
used to illuminate an area of 1.5 km × 1.5 km. Figures 2.57 and 2.58 show the
diagram of the module as well as the picture of it.
Similar VCSEL illuminators are used with silicon CCD or CMOS cameras
for illumination for perimeter security, area illumination, border security
etc. Figures 2.59 and 2.60 show diagrams for these illuminators that are small
form factor, have high efficiency, and have low cost.

2.12.11 VCSEL-Based 1064 nm Low-Noise Laser

PO developed a novel approach for low-noise lasers with extremely low noise
using VCSELs. For high-power operation, efficient heat removal is required