Related Experiment Video
Updated: Jun 7, 2026
08:39
Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator
Published on: January 28, 2019
Laser beam combiner for Thomson scattering core LIDAR.
1EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB, United Kingdom. itziar.balboa@ccfe.ac.uk
The Review of Scientific Instruments
|November 2, 2010
Summary
This study introduces a scanning mirror to combine multiple lasers for Thomson scattering diagnostics, enhancing tokamak repetition rates. This innovation improves laser pointing stability for fusion energy research.
Area of Science:
- Plasma physics
- Fusion energy research
- Optical diagnostics
Background:
- Thomson scattering (TS) is a crucial diagnostic for plasma measurement in tokamaks.
- Current TS systems using single, high-energy, short-pulse lasers have limited repetition rates.
- Increasing the repetition rate is essential for advanced fusion research and future reactors.
Purpose of the Study:
- To develop a novel laser beam combining system to increase the repetition rate of TS diagnostics.
- To assess the pointing stability and long-term reliability of the proposed system.
- To evaluate the system's potential application in major fusion devices like ITER and JET.
Main Methods:
- A scanning mirror was designed and implemented as a laser beam combiner.
- Position accuracy and jitter measurements were performed to quantify beam pointing stability.
- A control feedback loop was integrated to ensure long-term stability.
Main Results:
- The scanning mirror system demonstrated excellent laser beam pointing stability within ±25 μrad over tens of seconds.
- The implemented control feedback loop confirmed long-term operational stability.
- The system's design is compatible with the requirements of large-scale fusion experiments.
Conclusions:
- The developed scanning mirror system effectively increases the repetition rate of Thomson scattering diagnostics.
- The system offers high pointing stability and long-term reliability, crucial for fusion plasma research.
- This technology presents a viable solution for advanced diagnostics in ITER and JET.
Related Concept Videos
01:16Confocal Fluorescence Microscopy
Confocal microscopy is an advanced microscopic technique. The prime advantage of the confocal microscope over other microscopy techniques is its ability to block the out-of-focus light from the illuminated samples using pinholes. It is widely used with fluorescence optics to obtain high-resolution, sharp contrast images. Unlike optical microscopes, confocal microscopes use a focused beam of light laser to scan the entire sample surface at different z-planes. These microscopes are, therefore,...
01:05Total Internal Reflection Fluorescence Microscopy
Total internal reflection fluorescence microscopy or TIRF is an advanced microscopic technique used to visualize fluorophores in samples close to a solid surface with a higher refractive index, such as a glass coverslip. TIRF only allows fluorophores in proximity to the solid surface to be excited. When light from a medium with a lower refractive index (such as air) hits the glass coverslip at a critical angle, the light undergoes total internal reflection stead of passing through the glass.
01:26Inductively Coupled Plasma Atomic Emission Spectroscopy: Instrumentation
Inductively coupled plasma (ICP) is the common plasma source used in atomic emission spectroscopy (AES), a technique that detects and analyzes various elements in a sample. This method is often called inductively coupled plasma atomic emission spectroscopy (ICP-AES).
There are three main types of inductively coupled plasma atomic emission spectroscopy (ICP-AES) instruments: sequential, simultaneous multichannel, and Fourier transform instruments, with the latter being less commonly used.
There are three main types of inductively coupled plasma atomic emission spectroscopy (ICP-AES) instruments: sequential, simultaneous multichannel, and Fourier transform instruments, with the latter being less commonly used.
01:19Thomson's e/m Experiment
In a beam of charged particles created by a heated cathode, the particles move at different speeds. However, many applications need a beam with uniform particle speeds. An arrangement known as a velocity selector uses electric and magnetic fields to pick particles with a particular speed from the beam.
A particle with charge q, speed v, and mass m enters an area from the top, where the magnetic and electric fields are perpendicular both to the particle's motion and to one another. The magnetic...
A particle with charge q, speed v, and mass m enters an area from the top, where the magnetic and electric fields are perpendicular both to the particle's motion and to one another. The magnetic...