1. Diode Laser: Edge
Jerfey van Weelden

2. General Information Most common type of laser Low cost (mass product)
In 2004, 733 million compared to other type lasers
Low cost (mass product)
Use electrical current to power the laser
Light diode laser many different properties
Power
Wavelength

3. Semiconductor laser Semiconductor laser have a p-n junction.
Recombination in juction region
Resistance high in junction region
Homojunction
single junction of the n- and p- doped materials
high heat dissipation, not practical

4. Structure diode laser: edge
Double hetero structure
Two types of semiconductors
Potential barrier
Edge, light emitted parallel to surface junction
current through metal contact
Edge cleaved

5. Bandedge diagram hetero structure
Active region
Forward bias
Holes and electrons confined in active region

6. Properties Higher bias → higher output power
Different materials semiconductor → Different wavelengths
Continuous/pulsed bias → continuous/pulsed output
Small size

7. Applications Barcode readers Pumping other lasers Laser pointers
Dvd/cd-rom
Dentistry (soft tissue procedures)

8. Recent experiment
The Effects of a Diode Laser (810 nm) on Pigmented Guinea-pig Skin
E.M. Procaccini, G. Riccio, M. Bellocci, C. Di Martino and G. Monfrecola
2001
Only pigmented area’s damaged
absorbed by melanin
treating pigmented lesions without damaging the surrounding non-pigmented organelles