ORPHEUS User’s Manual
Light Conversion
21
5.
DESCRIPTION OF OPERATION
5.1
Overview
ORPHEUS is a two-stage optical parametric amplifier of the white light continuum. The device
employs computer-controlled translation and rotation stages for several key optical components, providing
fast automated wavelength tuning. The basic configuration consists of the several subunits:
1.
White light continuum generator.
2.
Second harmonic of the pump beam generator.
3.
First amplification stage (a
non-collinear
two pass pre-amplifier).
4.
Second amplification stage (a
collinear
power amplifier).
These subunits are arranged in a single compact housing. Layout of the subunits is shown in Figure 14
and the full optical layout of ORPHEUS is presented in Figure 15.
Figure 14. Layout of the ORPHEUS subunits
ORPHEUS can accept a variety of input pulse energies, repetition rates, beam sizes, etc. However,
during installation, it is set and optimized for fixed pump parameters, which should not change by more
than ±10
% for ORPHEUS to operate. A decrease of pump pulse intensity might lead to lower efficiency of
ORPHEUS, narrower spectral widths or even no output if white light generation cannot be obtained. An
increase of pump pulse intensity poses a risk of damaging several optical components and non-linear
crystals. If it is needed to operate ORPHEUS at different pump pulse parameters
–
replacement of several
optical components and realignment should be performed to match new pump conditions, and it is usually
done by a trained engineer. This manual does not cover the option of operating ORPHEUS with variable
pump pulse parameters.
The beams present inside ORPHEUS are dangerous not only to the human eye or skin, they can also
heat and cause damage to the internal mechanical and optical components if the device is not aligned
properly. Reflection shields and protective covers are used inside ORPHEUS to catch most of the unwanted
reflections and residual radiation before it reaches the sensitive components. It is highly recommended to
block the pump beam (close the shutter) whenever the system is not in use.