New High Voltage Analogue Amplifiers
As part of our ever growing range of products we have added two new high voltage analogue amplifier designs. Intended to bridge the gap between our high-bandwidth/low-voltage M250 and high-voltage/low bandwidth M5000 models, this pair of new amplifiers offer peak to peak differential swings of 1000V and 2500V respectively which are ideal for use with larger aperture transverse field modulators such as our EM400 and EM600 series devices.
Ultra-Wide Tuning Range Faraday Isolator
Here at Leysop we are very excited about our new ultra wide tuning range Faraday isolator. This is a total departure in operational style from our other devices in that the adjustment of the wavelength of maximum isolation is achieved using a very smooth action helicoidal adjustment ring. There is no requirement in this unit to remove and re-fit polarizers to fine tune or re-assign the unit to a new wavelength. Incredibly, this adjustment is able to produce a smooth tuning of the rejected wavelength over a range of over 400nm. A typical device for example could provide maximum isolation from 650-1,100nm, without rotation of the TGG rod or any of the polarizing optics (which are still of course our excellent quality calcite Glan-Taylor polarizers).There will be an outline control drawing to follow soon; watch this space. If you would like to discuss this new unit or obtain pricing information, please do not hesitate to contact us.
Ultra-Miniature Longitudinal Field KD*P Pockels CellThe design of the Pockels cell has changed little over the years. The basic ring electrode format of the longitudinal field design KD*P Pockels cell is well proven and so there is no merit in changing the fundamentals of this trusted design. However, applications do move on and increasingly designers are looking to build ever more compact laser systems. We have responded to this with the introduction of our new ultra-miniature EM510C device. This packages a 10mm diameter crystal, in a housing of only 25mm diameter and 43mm length. For details take a look at the interface drawing.
The clear optical aperture is defined at 8mm diameter by a ceramic disc. Of course, a small package would be nothing if the cell's performance was compromised by the design. However, rest assured this device provides the same excellent performance as our other compact 10mm Pockels cell, the EM510M. The main difference (apart from package size of course) is that this new smaller cell is available at this time only as a dry cell, that is the crystal and windows are both anti-reflection coated and no index matching fluorocarbon fluid is used. For applications for which transmission is critical we can supply this device with a polymer AR coating which offers very low reflection losses, giving a peak transmission of as high as 98% and a very broad bandwidth response. Please enquire if this is of interest to you. For information on our other Pockels cells click here.
Pockels Cells with Integrated Wave-Plate and Brewster PolarizerProbably the most common and attractive mode of operation of an electro-optic Q-switch is in "pulsed quarter wave" mode. In this mode a quarter wave retardation plate is inserted between the Pockels cell and the rear cavity mirror. Light passing through the Pockels cell at zero applied voltage is unaffected but on passing twice through the wave-plate its polarization axis is rotated through 90°. In systems with correcly aligned polarizing gain media such as Nd:YVO4 the light is in the wrong polarization to receive significant gain and the cavity is operating at low Q. With non-polarizing media such as Nd:YAG, an additional polarizing element must be inserted between the Pockels cell and the gain medium to force single polarization operation. When a pulse of the correct quarter wave retardation voltage is applied to the Pockels cell, it introduces a double pass polarization axis rotation of a further 90° and the overall effect is of no polarization rotation, hence the cavity is switched rapidly to a high Q condition and the medium is Q-switched.
This simple approach has several advantages over other techniques, notably, the operation of the Pockels cell at the lower quarter wave voltage (using one quarter the electrical power of a half wave switching system) and no d.c. voltage is applied to the Pockels cell which extends its operating lifetime. However, the drawback is the additional effort required to mount and align the wave-plate and (if necessary) the additional polarizing element. With these pre-aligned and integrated onto the Pockels cell by us, the device offers a considerably easier way to obtain the advantages of pulsed quarter wave switching. High quality low insertion loss wave-plates and Brewster polarizers ensure that your system operates at its optimum and the Brewster polarizer mounting acts as an effective beam dump for the rejected light, thus simplifying the handling of stray light. For information on our other Pockels cells click here.
RTP Pockels Cell System for High Repetition Rate Q-SwitchingQ-switched lasers operating at high repetition rates have traditionally been the province of acousto-optic Q-switches. The very same acousto-optic effect which enables this technology has been the bane of electro-optic Q-switches for all but low frequency applications. Even the much vaunted BBO Pockels cell has only been operated commercially to frequencies around 30kHz before acoustic resonances begin to appear and upset the Q-switching process. RTP by comparison has been demonstrated to be free from the effects of acoustic resonances out to at least 200kHz and probably beyond. For applications in moderate average power lasers (i.e. a few watts average power and maybe even up to 10W) RTP looks an exciting new development and we strongly urge all manufacturers of such lasers interested in improving pulse lengths compared to acousto-optic q-switches to try RTP and find out what it can do for them.
For exploring the potential of this new Q-switch we can supply a fully featured 100kHz Q-switch driver at low cost. What are you waiting for? Give it a try. For more information on these and our other Pockels cells click here.