Available Photonics Experiments:

P5863 Frequency doubling (DPSSL) PDF Download page

  • Nd:YAG laser
  • Nonlinear optics
  • Phase matching condition
  • Conversion efficiency
  • Verification of quadratically relationship SHG power
  • Clear demonstration of transverse modes
  • Intra cavity iris for TEMoo operation
Principle of operation
Inside the cavity formed by the mirror (M1) and (M2) a KTP crystal is placed. The fundamental radiation is frequency doubled generating visible green radiation at the wavelength of 532 nm. The filter (F) blocks the pump as well as fundamental radiation in such a way that only green radiation can be characterised.
  • Examples of investigations and measurements
Characterization of diode pumped Nd:YAG laser
All experiments and measurements performed with XP-06 Nd:YAG laser can be done as well with this setup.
In addition a KTP crystal (K) and the filter BG-39 (F) is provided which turns the XP-06 experiment into a set-up for frequency doubling.
XP-07.03 Second harmonic generation
After aligning the basic set-up in the same way as already shown in XP-06 the KTP crystal assembly (16) is inserted inside the cavity It can be turned inside the adjustment holder for best phase matching indicated by highest green output power. Four fine pitch adjustment screws are used to align the crystal with respect to the optical axis of the laser cavity. The intensity of the second harmonic is measured as function of the fundamental power and the injection current of the pump laser respectively. The evaluation of the data will show the expected quadratic behaviour.
XP-07.05 Demonstration of transverse modes
Due to the high gain of the Nd:YAG material a lot of transverse modes are generated. Also from these modes second harmonics are generated and are visible due to their wavelength of 532 nm.
By placing the adjustable iris into the cavity close to the right mirror (12) the number of transverse modes can be reduced significantly down to pure TEM00. This can be observed on a wall or white sheet of paper when the photodetector and filter is removed. In principle the BG-39 filter (7) can remain to avoid infrared emission leaving the system.
  • P5863 Non linear optics, Second Harmonic Generation consisting of:
Item Code Qty Description
1 3L-0200 2 BNC cable, BNC connector both sides, 1,5 m
2 ED-0020 1 Digital controller for injection current and temperature
3 ED-0060 1 Photodetector signal conditioning box
4 MC-0005 1 Profile rail MG-65, 500 mm
5 MC-0120 1 Crossed hair target in holder 25 mm
6 PM-0070 1 Infrared display card, range 0.8 -1.6 µm
7 PM-0250 1 RG1000 Coloured glass filter 50 x 50 x4 mm
8 PM-0260 1 BG39 Coloured glass filter
9 XM-0020 1 Module A - Diode laser in adjustment holder
10 XM-0030 1 Module B - Collimating optics on carrier
11 XM-0040 1 Module F - Focussing optics, f=60 mm
12 XM-0050 1 Module D - Mirror adjustment holder with Nd:YAG rod
13 XM-0060 1 Module E - Adjustment holder “right” with laser mirror SHG 100
14 XM-0070 1 Module F - Filter plate holder
15 XM-0080 1 Module G - SiPIN photodetector
16 XM-0090 1 Module K - KTP crystal for SHG with adjustment holder on carrier MG-65
17 XM-0220 1 Optics cleaning set
Required Options:
18 TP-0100 1 Oscilloscope 100 MHz digital, two channel
20 XM-0370 1 Spatial filter with adjustable iris diaphragm