Technology news
For the latest technology news from the photonics industry go to
www.electrooptics.com/technology
MeMs-based, low wobble scanners
Researchers at the Fraunhofer IPMS have developed a customised silicon-based resonant and quasi-static micro- electromechanical system (MEMS) for deflection and modulation of light. The device is intended as a replacement for conventional galvanometer- based optical scanners. The design of conventional scanners can limit the precision of motion, particularly at high velocity. A characteristic measure
for the quality of scanner motion is the dynamic mirror tilt, perpendicular to the axis of rotation. Mirror tilt leads to a tumbling motion and a deformation of the scanned beam, often referred to as cross-axes wobble. Cross-axes wobble of conventional resonant galvanometer scanners is typically in the order of 200µrad. The silicon-based resonant and quasi-static micro- electromechanical system developed by Fraunhofer offers high velocity scanning with superior precision, and the researchers have now demonstrated that typical resonant designs provide a cross-axes wobble of less than 35µrad. The device oscillates at 23kHz with a mechanical amplitude of ±9°. Dr André Dreyhaupt, scientist at the microscanner product development group, stated: ‘The optical MEMS structures of the Fraunhofer IPMS perfectly fit for challenging applications with high demands on velocity and precision of motion at the same time.’
Femtosecond laser system achieves record power and perfect beam
Research scientists from the Fraunhofer Institute for Laser Technology ILT in Aachen have installed a femtosecond laser at the Max Planck Institute of Quantum Optics (MPQ) in Garching, as part of the Korona cooperation. The project claims it is the first ever laser to generate an average power of 280W at 515nm with perfect beam quality. The turn-key laser is based on a Yb:Innoslab amplifier with frequency doubling. It is claimed that no other laser system has ever offered more output with diffraction-limited beam quality in the visible spectral range. Ultrashort laser pulses are an established tool in science and industry. In many areas, the range of applications can be expanded by scaling them up to high average output power. In recent years, beam source development has seen great progress on this front. Average output power of several hundred Watts, with diffraction-limited beam quality, have been demonstrated using ytterbium-doped laser media at 1µm wavelength in fibre, Innoslab and thin-disk geometries. The Fraunhofer ILT scientists hold the record with their Yb:Innoslab amplifier, generating an
output power of 1.1 kW. These beam sources must be reliable and easy
to operate if they are to be used widely in science. The scientists from Fraunhofer ILT have installed a laser system at the MPQ, delivering an average power of 280W at 515nm and an almost diffraction- limited beam quality of M2
construction and user interface. It works by amplifying the radiation from a
commercial femtosecond laser with 3W output power in a Yb:Innoslab amplifier to 470W at a pulse duration of 700fs and then doubling its frequency in a non- linear crystal.
› 1.4 using near-industrial
LZH develops picosecond fibre laser for micro-machining
Together with six industrial partners, Laser Zentrum Hannover (LZH) has developed a picosecond laser system based on fibre lasers. This system, developed as part of the research project called PULSAR (PUlsed Laser System with Adaptive Pulse PaRameters), has achieved excellent micro-machining results for brass and aluminium. The system fulfils many of the
requirements for industrial use. It is especially flexible and adaptable to different settings because the laser oscillator and amplifier are separate. Depending on the material and the desired process
14 ELEctro optics l JUNe 2011
results, the repetition frequency and the average output can be adapted to the current process. A laser diode with a wavelength of 1.03µm and a pulse length of approximately 40ps serves as the pulse source. The pulse repetition rate is flexible, and can be set between 50kHz and 40Mhz. Using a three-step amplifier, the pulse can be amplified from 10µW to an average output power of 14W. At a repetition rate of 1MHz, a pulse energy of 14µJ is possible. The fibre-based, picosecond laser system has an excellent beam quality, and is resistant to difficult
production environments, such as dust contamination, temperature fluctuation, or mechanical vibrations. Also, very good results in working aluminium or brass have been achieved. Also, the system is small and less expensive than conventional solid-state lasers. There are many applications for this high-power laser; among them marking aluminium, or for making stamps of hard metal (V70) such as for stamping coins. The project is subsidised by the BMBF initiative INLAS (Integrated-optical Components for High-power Laser Sources).
www.electrooptics.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36