Available Photonics Experiments:

P5867 Diode pumped Nd:YVO4 Micro Laser
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  • Diode laser
  • Optical pumping
  • Nd:YVO4 laser
  • Spiking
  • Laser threshold
  • Slope efficiency
  • Second harmonic generation
  • Examples of investigations and measurements
Principle of operation
A green core laser (GCL) has a size of 1.3 x 1.3 x 3 mm and consists of a Neodymium Yttrium Vanadate (Nd:YVO4) crystal which is cemented to a KTP crystal. The outer side (M1) of the Nd:YVO4 is coated in such a way that it transmits the emission of the pump diode laser and reflects the fundamental radiation at 1064 nm and the second harmonic at 532 nm. The mirror M2 forms the second cavity mirror and is designed of high reflectivity of the fundamental wave and high transmission for the second harmonic. Once the laser reaches the threshold radiation at 1064 and 532 nm are emitted.
OX General setup
The laser diode (8) emits the pump radiation at 808 nm and the divergent radiation is collimated by a three element lens system (9) and subsequently focussed with the single lens (10) having a focal length of 60 mm. The GCL (14) is mounted into a special holder to provide efficient passive heat dissipation. The GCL is positioned in such a way that the focus of the pump radiation lies well within the Nd:YVO4 crystal. As soon as the laser reaches its threshold also green light is created. To study only the fundamental radiation a RG1000 filter(6) is placed in front of the photodetector (12). The signal conditioning box (2) provides a BNC output which is connected to the oscilloscope.
OX Alignment procedure
The pump laser radiation is collimated (9) and centred to the optical axis of the optical axis of the rail. The pump radiation can be seen on white or black background, thus a crossed hair target (4) can serve as an alignment aid. Once the radiation is almost parallel and aligned to the optical axis the focussing lens (10) is placed onto the rail. With a white sheet of paper the position of the focus is searched and noted by the reading of the ruler of the rail. At this position the GCL is placed. The output power is maximised by realigning the pump laser and moving the focussing lens.
OX Measurements
The pump laser diode is connected to the digital controller (1) which allows the variation of the injection current and temperature. In a first step the laser diode is characterised by this parameters. Operating the GCL allows the measurement of the static laser properties like threshold and out put power related to the pump power. The controller also allows the modulation of the injection current of the pump laser so that the dynamic properties like spiking and pump depletion can be studied.
  • P5867 DPSS Micro laser:
1ED-00201Digital diode laser controller
2ED-00601Photodetector signal conditioning box
3MC-00051Profile rail MG-65, 500 mm
4MC-01201Crossed hair target mounted in holder 25 mm
5PM-00701Infrared display card, spectral range 0.8 -1.6 �m
6PM-02501RG1000 Coloured glass filter 50x50x4 mm
7TP-00101Set of 3 BNC cables each 1 m
8XM-00201Module A - Diode laser head, adjustment holder
9XM-00301Module B - Collimating optics on carrier MG-65
10XM-00401Module C - Focussing optics, f=60 mm
11XM-00701Module F - Filter plate holder
12XM-00801Module G - SiPIN photodetector
13XM-02201Optics cleaning set
14XM-14101GCL, mounted on carrier 20 mm
 Required Options:  
 TP-01001Oscilloscope 100 MHz digital, two channel