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Figure 2. The illustration of divergence angle of laser
emitting (Hu, 2005)
Laser source T ee
Screen
Prism
Rapid Stow
Alignment Alignment
Figure 3. Simulated alignment of laser emitting system
Figure 4. Simulated 3D model for alignment of laser
emitting system
3. COMPONENTS OF LIGHT-EMITING SYSTEM
3.1 Laser Diode
TPGAS2S09H diode laser with wavelength of 905 nm is
used for this project. Diode lasers in the 1300 nm to 1600
nm regime are used in a variety of applications including
pumping, range finding, materials processing, and
aesthetic medical treatments. In addition to the compact
size, efficiency, and low cost advantages of traditional
diode lasers, high power semiconductor lasers in the eye-
safe regime are becoming widely used in an effort to
minimize the unintended impact of potentially hazardous
scattered optical radiation from the laser source, the
optical delivery system, or the target itself.
The laser diode has the following characteristics (see
Figure 5):
— Peak power >300 W at 30 A driving current and
100 ns pulse width.
— 905 nm pulsed laser output.
- Extremely high reliability.
- Small emitting areas allow ease of lens or fiber
coupling.
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B3, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
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Figure 5. (a) Package drawing and (b) its spectral plot
distribution ( http://www.perkinelmer.com/
CMSResources /Images/44-6562DTS_HighPowerLaser
DiodesforRange Finding.pdf)
The junction plane, light-emitting surface and divergence
angle of diode laser are depicted in Figure. As seen, the
light-emitting surface is not symmetric with the
divergence angle. For each light-emitting element, the
length in the directtion parallel to junction plane is about
230 um, and the height in the direction of vertical to
junction plane is 1pm. The divergence angles in direction
parallel to and vertical to junction plane is 10° and 25°,
respectively. The major functionality of light-emitting
optical system of diode laser is aligning and shaping to
the bundle of light, which are no-symmetric, big
divergence angle and poor quality, to make them meet
the requirement of laser, i.e., small divergence angle,
alignment and high energetic light.
The final required bundle of laser is: Divergence angles
in horizontal and vertical direction is approximately
30~33mrad, the energy Transmittance laser reach above
95%.
230um
2
Junction plane epo
lum —
1 Lightemitting surface
10* E
Figure 6. Illustration of ligh-emitting surface and
divergencey angle.
This laser emitting sub-system is to generate high energy
of laser. As a initial research, a prototype with 5 x 5
