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FAQ: BMC Deformable Mirrors for Laser Applications:Power

Posted by Angelica Perrone on Wed, Apr 02, 2014 @ 12:00 PM

Tags: deformable mirror, adaptive optics, boston micromachines, Boston University, laser beam, laser science, BMC, Mirrors, pulse, pulse width, peak power, laser pulse shaping, ultrafast lasers, laser pulse compression

About half of our customers use our deformable mirrors for laser applications, such as beam shaping or steering. We get a lot of questions pertaining to laser power and handling for both our deformable mirrors and modulators.  Below is a summary of the guidelines we use when discussing our technolgy.

The most important specification to note immediately if you are working with lasers is the damage threshold of our DM's. There are two mechanisms of failure to consider: mirror damage due to heating and coating delamination.  The first failure mode is largely governed by the average power experienced by the DM. The rule of thumb that we follow is maximum average power of 20W/cm². For the second failure mode, the peak energy is of greatest concern.  In this case, the threshold that we use is that of a standard thin-film gold metallic coating, in this case, 0.4J/cm². Depending on the DM system, the calculations may be slightly different. In order to ensure a DM is suitable for your application, we typically need to know as many of the following properties as possible: the pulse width of the laser, peak power, frequency, wavelength and beam size. This last pameter will help to determine which aperture size is required and if you need to change your beam size at all. Additional information on laser power can be found on our previous blog here.

From a power threshold standpoint, our modulator technology works similarly to our deformable mirror technology. However, it may have a slightly lower damage threshold due to the fact that the exposed surface is a thin layer of silicon nitride as opposed to the thicker polysilicon surface used for our deformable mirrors. Honestly, we do not have much experience testing the devices.  If you are interested in carrying out testing, we would be glad to lend you some modulators to test.

If you are interested in learning more about customers' experience with high-power lasers used on our DM's, please click here to read Andrew Norton's paper on laser test performed using our DMs. Also, please visit our website or contact us for questions or additional information on how to obtain a device for testing.

Further focus at CLEO 2013

Posted by Michael Feinberg on Tue, Jul 09, 2013 @ 12:54 PM

Tags: deformable mirror, adaptive optics, boston micromachines, laser beam, laser science, biological imaging, deep tissue microscopy, BMC, two photon, free-space communication, modulating retroreflector, optical chopper, optical modulator, chopper, UAV, pulse, pulse width, laser pulse shaping, ultrafast lasers, CLEO, AOM, acousto-optic modulator, speed, shutter

It's been a few weeks since we returned frocleo resized 600m the Conference on Lasers and Electro-Optics 2013 and now that we're settled back in to the daily routine, I thought I would give some highlights on the show. I was happy to be joined this time by our new Marketing and Communications Specialist, Angelica Perrone, who did a great job navigating the complex photonics market for the first time.

While the conference seems to be chugging along at a nice pace, the tradeshow has most definitely become a smaller venue.  We were once again hosted by our strategic partner, Thorlabs (thanks, again guys!) and being in such a central location on the floor, we were able to get a good flavor for the pace of the show.  Here are my thoughts:

Little, different, yellow, better

Anybody get that Nuprin reference?  Anybody? See what I 'm talking about here.

Okay, so it's not yellow (although yellow lasers are cool), but the show is definitely getting smaller.  I mentioned to a colleague that since the show is in San Jose for the second year in the row, it seemed like the barriers on either end of the tradeshow floor had moved in just a bit. 

As far as different, the show is not like other photonics shows in that it is pretty focused in its applications.  While there were some interesting talks on microscopy, this was a small portion of the material, with most others focussing on more laser-centric applications, as the title of the conference implies. 

As far as better, I would say that for BMC, it was most definitely better for our new products:  The Reflective Optical Chopper(ROC) and the Linear Array DM.  We recieved more interest in these products over our legacy deformable mirror technologies. This is exciting for me as a product marketer and salesperson and even moreso as a member of a company that is always looking for new avenues for our technology. We see the ROC being useful for users who span from pure laser scientists to imaging engineers interested in chopping a beam at high speed with either a constant or variable duty cycle.  The linear array has already proven useful in pulse shaping applications as described in our whitepaper, which is available for download here.  Both products are available for purchase now.

Our Wavefront Sensorless Adaptive Optics Demonstrator for Beam Shaping (WSAOD-B)also generated some buzz. More and more applications which require wavefront correction are surfacing and need a solution without a wavefront sensor.

In all, it was a good show that has given me and my team work to do as we explore more exotic applications for our technology.  I look forward to joining the show again next year and I hope to connect with all of you again in the near future!

For more information on the products mentioned above, please visit our website and download our whitepapers.

Fast and Precise Laser Pulse Compression with the Linear Array DM

Posted by Michael Feinberg on Wed, Nov 07, 2012 @ 10:33 AM

Tags: deformable mirror, adaptive optics, boston micromachines, laser science, Janelia Farm Research Campus, microscopy, laser pulse shaping, ultrafast lasers

Linear ArrayUltrafast lasers have been extensively used in ground breaking  research including two Nobel Prizes.  Applications within spectroscopy, photochemistry, laser processing and microscopy are widespread.  However, to capitalize on such short laser pulses, a pulse compressor is required to compensate for the dispersion induced by optical elements. Liquid crystal based spatial light modulators are most commonly used in laser pulse compressors.  Although a proven technology in display applications, liquid crystals have drawbacks including phase jitter and a limited fill factor.  Researchers at the Cui Lab at HHMI’s Janelia Farm Research Campus looked to Boston Micromachines Corporation’s prototype Linear Array Deformable Mirror (DM) to address these challenges.

To evaluate the performance of the pulse compressor, the laser pulses were analyzed with frequency resolved optical gating (FROG) using a commercial instrument (Grenouille, Swamp Optics, Atlanta, GA). In Figure a and b, the temporal and spectral profile of the pulse is shown when a flat wavefront is displayed on the DM. Evidently, the pulse is distorted and the spectral phase is not flat at all (a flat spectral phase is required for a transform limited pulse). Next, the beam returning from the pulse compressor was focused with a concave mirror onto a GaAsP photodiode and the resulting nonlinear signal was used as a feedback for the correction algorithm. After optimization using a technique called Phase resolved interferometric spectral modulation (PRISM), the temporal profile (Figure c) shows a dramatically shorter, Gaussian shaped pulse. The spectral phase is perfectly flat (Figure d) with less than 0.01 radians phase error and is stable in time. These results suggest that the precision and stability of the Linear Array DM allows close to perfect restoration of transform limited laser pulses.  For more information on the optimization technique, you can access a scientific publication here.

 

 pulse compression, FROG, pulse shaper

 

In our next blog post, we will discuss the results of the use of the Linear Array DM in an interesting two-photon microscopy experiment.

More details can be found in our Linear Array white paper which includes a more detailed description of this application.