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FAQ: BMC Deformable Mirrors: Windows

Posted by Angelica Perrone on Wed, Mar 26, 2014 @ 09:51 AM

Tags: deformable mirror, laser beam, laser science, ultrafast lasers, CW, Coatings


For those interested in using our deformable mirrors with laser applications, there are a few common questions which are asked in regards to the AR-coated window and if it is/can be removable.  Below is a summary of what's standard and what's possible:

Both the optical modulator and our DMs are protected by a 3mm thick window, which are standard BK-7 windows from Thorlabs. The options for windows are: 

  • 350-700nm
  • 400-1100nm
  • 650-1050nm
  • 1050-1620nm
  • 550nm-2400nm

This can also be customized upon request. The windows are mounted on a 6° angle in order to prevent ghosting. 

A lot of requests are in regards to removing the protective window. For our standard DMs, the window is not removable as it is attached with an epoxy. For our modulators, the window IS removable. We highly recommend you DO NOT REMOVE the protective window. The only exception to not having an AR-coated window would be if the DM was operated in a clean room environment.  In this case, we can deliver the modulator or DM without the window and include a protective removable lid instead. In addition, we recommend flowing Nitrogen at a very slow pace around the mirror to ensure the humidity remains low around the DM. The required humidity is <30% as the mirror is made of polysilicon which needs to be protected from corrosion. 

 Please visit our website or contact us for additional questions.

deformable mirrors, BMC,adaptive optics

Photonics West/BiOS Exhibition Recap

Posted by Angelica Perrone on Wed, Feb 26, 2014 @ 11:45 AM

Tags: deformable mirror, adaptive optics, boston micromachines, laser beam, deep tissue microscopy, SLM, spatial light modulator, BMC, imaging systems, two photon, retinal imaging, free-space communication, modulating retroreflector, segmented, SPIE, Photonics West, microscopy, optical chopper, optical modulator, chopper, Adaptive Optics Scanning Laser Ohphthalmoscope, Joslin Diabetes Center, Mirrors

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Just a few weeks ago we arrived back from the Photonics West 2014 exhibition and conference in San Francisco, CA. I wanted to share details and further observations on the show for those present at the show and those not being able to attend this year. 

For the first time we made the decision to also attend the BiOS exhibition for the few days prior to PWest. Not being quite sure what to expect for booth traffic, especially since it conflicted with the superbowl, we still generated a good amount of interest for the smaller show. Our main presentations focused on our new adaptive optics-enhanced scanning laser ophthamoscope (AOSLO), the Apaeros Retinal Imaging System, which includes our Multi-DM, and the Superpenetration Multiphoton Microscopy technique, which is enabled by our Kilo-SLM and high speed S-Driver. Although both exhibits generated respectable notice and positive feedback, most people were familiar with the Superpentration Multiphoton work being done. Either wanting to try two-photon microscopy themselves or already in the process of doing so, our Kilo-SLM paired with our high speed S-driver presented data that was intriguing to most.

After wrapping up BiOS, we headed to the opposite side of the South hall at the Moscone Center for a larger booth setup for PWest. Here we had our entire mirror family on display, as well as live demonstrations of the Reflective Optical Chopper and Wavefront Sensorless Adaptive Optics Demonstrator for Beam Shaping (WSAOD-B). For this part of the exhibition, I would say our deformable mirrors produced the most attention, most likely due to our wide assortment of shapes and actuator counts up to 4092. The WSAOD-B live demonstration did generate a great deal of attention, as most people are unaware of how sensorless AO works. Besides our deformable mirror line, I would still say the Multiphoton Microscopy overview was initiating even further interest here as well.

Overall BMC had a great show and it seemed well worth it to expand our exhibit onto BiOS beforehand. Although this was my first time attending the show, I noticed every inch of space at PWest being used for exhibitor tables and booths, even setting up in front of the bathrooms! I hope to see PWest advance even larger, maybe one day expanding to its third space, West Hall. I look forward to next year’s show and hope to reconnect with you all again throughout the year.

If you were not able to attend the show and would like any information on the products mentioned, please visit our website and download our whitepapers

FAQ: Flatness of BMC Deformable Mirrors

Posted by Angelica Perrone on Thu, Jan 16, 2014 @ 11:36 AM

Tags: deformable mirror, adaptive optics, boston micromachines, mirror technology, spatial light modulator, BMC, imaging systems, Mirrors

Happy New Year! Hope everyone had a great holiday and is staying warm.

To continue addressing our FAQ's, another recurring question BMC recieves is on the flatness of our deformable mirrors.  The figure below shows an unpowered BMC DM and a flattened BMC DM. 

Flatness

The surface figure of our unpowered deformable mirrors has a low-order surface bow. The amount of stroke needed to flatten the DM is between .5 µm and 1 µm, depending on the model. We can guarantee that the stroke needed to flatten the deformable mirror will not exceed this amount and tends to be lower for the lower stroke devices.

However, researchers in the past have been able to achieve flattening the wavefront without using up any stroke on the DM. If you are able to include additional optics into your setup, the low order bow can be taken out with static optics. Just something to keep in mind as you are designing your system and trying to determine how much stroke is required to achieve your wavefront correction needs.

If you have any additional questions in regards to the flatness of our mirrors or are interested in seeing what the typical unpowered surface figure is, please contact us at moreinfo@bostonmicromachines.com or visit us online at www.bostonmicromachines.com

FAQ: BMC Deformable Mirror Reflectivity

Posted by Angelica Perrone on Fri, Dec 20, 2013 @ 09:00 AM

Tags: deformable mirror, adaptive optics, boston micromachines, product information, mirror technology, BMC, Mirrors, Coatings, Reflectivity, Thorlabs

Over the past couple of months we have been receiving an assortment of questions in regards to our products. We thought it would be a good idea to share the more popular questions and answers as they stream in to keep everyone updated.

One question that tends to be asked quite often is the reflectivity our deformable mirrors can achieve. This depends on a couple of factors such as mirror coating, protective window AR coating and the wavelength of the light. 

Figure 1

We offer gold, aluminum and protected silver coating on almost all of our deformable mirrors. When selecting a coating, you should pay particular attention to the wavelength(s) of light you use. The BMC DM Coating Reflectivity chart to the right illustrates the reflectivity of each of our standard coatings.

Our standard windows with AR coating are BK-7.  We offer a few options, depending on which size mirror you select.  For our smaller DMs, we offer the standard coatings from Thorlabs as well as a few more versatile options.  You may choose either uncoated, 350-700nm, 650-1050nm or 1050-1620nm.  We also offer a 400-1100nm window and 550-2400nm, the latter for an additional cost.  For our larger DMs, various coating options are available. We do offer customizable options for an extra fee, so please contact us with your specifications if you require this.

The N-BK7 Broadband Antireflection Coatings chart from Thorlabs below depicts the percentage of  light lost for each AR coated window. Similar curves are available for our other coatings.Antireflection coatings Thorlabs
               

If you are looking for additional information on our standard windows, please visit our friends at Thorlabs online. If you have any further questions on the reflectivity of our mirrors, click here to send us an e-mail or visit us online at www.bostonmicromachines.com

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.

What Do You REALLY Want in a Deformable Mirror?

Posted by Michael Feinberg on Wed, Oct 17, 2012 @ 04:00 PM

Tags: deformable mirror, adaptive optics, response time, laser science, mirror technology, microscopy, astronomy

This past summer, Boston Micromachines Corporation conducted a survey of nearly 300 members of the business and scientific community to find out what features were valued in a deformable mirror for adaptive optics and other wavefront correction applications.  Respondents came from our three major vertical markets: microscopy, deformable mirror survey resized 600astronomy and laser science.  In this survey, we asked some fundamental questions and had respondents choose between three DMs with properties varying in categories of actuator count, stroke, response time and price in various combinations. We were able to drill down to what each respondent valued.  Here are some of our key findings:

1)      Actuator count was the most valued property

Across all verticals, this was true.  Overall, respondents preferred an  average of 1000 actuators. While microscopists preferred 140 actuators by almost 2 to 1 over other models, those who identified as laser scientists were looking for an average of 1001 actuators and astronomers preferred, on average, 1800 actuators.

This was very interesting to us considering we are the only player in the market to provide deformable mirrors with these actuator counts as standard products or are developing DM systems which meet these specific needs (we have a 2000 element mirror in the works).

2)      High speed is important

The most frequently chosen option for response time amongst laser scientists was 50μs and all other disciplines preferred average response better than 300μs. This is great news for the industry considering that most mirror architectures can respond adequately to meet the needs of the users. Our DM architectures are available with response times up to 22μs and we are able to drive these mirrors with our X-Driver (response time down to 4μs), satisfying high speed requirements as well.

3)      Low price is desired

As we hear so often, most users were looking for low-priced devices. This was the second    preferred property after actuator count. While those of us in the industry talk about lower prices with higher volumes, the volumes just haven’t been there yet to make this prophecy come true.  The hope in the future is that the DMs based on scalable technologies, such as MEMS, will take off and lower-priced devices will be available.

We definitely learned a lot from this survey, above and beyond what is mentioned above.  If you have any questions about our methods or are interested in discussing more specifics about the responses, I would be glad to chat further.  Just contact me at support@bostonmicromachines.com.

 

Wavefront Sensorless Adaptive Optics Now a Reality

Posted by Michael Feinberg on Mon, Oct 01, 2012 @ 11:57 AM

Tags: deformable mirror, adaptive optics, boston micromachines, laser beam, laser science, mirror technology

WASO for blog

 

Up until recently nearly all adaptive optics (AO) systems used wavefront sensors for correction. But with recent advances, off-the-shelf wavefront sensorless AO is becoming a reality.  Benefits of this type of AO include enhanced aberration correction due to the elimination of non-common path errors and wavefront sensor noise.

BMC has developed a Wavefront Sensorless AO Demonstrator (WS-AOD) which provides a platform for utilizing metric-based wavefront control with BMC MEMS deformable mirror (DM) technology. While conventional AO systems perform closed-loop DM control using direct measurements of the wavefront as feedback, the metric-based approach uses details in the aberrated light to improve clarity. Two versions are available; one is optimized for beam shaping applications and the other is designed for imaging applications.

We see laser beam shaping as a key area in this exciting technology and our demonstrator is built to address the unique challenges of this field. Our WS-AOD serves as an introduction to wavefront sensorless adaptive optics principles. It allows users to understand the details involved in properly implementing a metric-based adaptive optics solution on an optical system. The demonstrator can also be used as a stand-alone aberration compensator. By introducing aberrations in the sample stage, the system can be optimized for a multitude of use cases from laser research applications to scanning laser microscopy. Additionally, the user can easily integrate the hardware into an existing optical system and utilize the open source software code for metric-based correction.

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Schematic of WS-AOD for beam shaping applications. Also available for imaging applications.

To compensate for phase aberrations the WS-AOD uses BMC’s deformable mirror (DM) technology. BMC’s DM is a continuous facesheet deformable mirror that is controlled by hysteresis-free electrostatic actuators located on a square grid. The full DM activemulti DM aperture can be as little as 1.5 mm to as much as 25 mm across. Each actuator can provide up to 5.5 µm of mechanical stroke, which corresponds to about 11 µm of phase control. The electrostatic actuator array is driven using independent high voltage channels with 14-bit resolution. This corresponds to sub-nanometer displacement precision. The drive electronics can provide frame rates of from about 4.6 kHz up to 100 kHz.

The control software for WS-AOD allows the user to correct for aberrations introduced as well as generate a random aberration using the DM. The software is open source code based in Mathwork’s Matlab and runs on platforms using Windows operating systems. By utilizing the included algorithm to manipulate the mirror surface, the mirror compensates for aberrations and converges to an optimal profile. The user has access to the open source code to balance correction capability between maximum signal and minimal time.

To learn more please click here for a copy of our Wavefront Sensorless Adaptive Optics white paper.

SPIE Mirror Tech Days: Highlights and Takeaways

Posted by Michael Feinberg on Wed, Sep 05, 2012 @ 02:11 PM

Tags: deformable mirror, mirror technology, BMC, imaging systems, SPIE, Photonics West, telescopes, NASA, SBIR/STTR

 

describe the imageThe SPIE Mirror Technology SBIR/STTR Workshop was held in Rochester, NY this year at the end of July. This is always a good conference for BMC, and we go every year.  The conference can best be summarized from their website:

Tech Days annually summarizes the USA Government's investment strategies and activities in developing technology for any application (such as telescopes, imaging systems, seeker/trackers, high-energy laser systems, solar energy, etc.) which requires optical components. Tech Days covers technology investment efforts in: optical materials; substrate design & manufacture; optical fabrication and metrology technology; optical coatings; wavefront sensing and control via adaptive optics; nano-technology imaging technologies; etc.

I highlighted the text for emphasis as to why we attend:  You can see why this is a great place for BMC to be. We get to present the latest progress on our NASA SBIRs (of which we have 4 ongoing), see some of the other great research that is going on in the field, and learn from the NASA Program Scientist what the future needs are for mirror technology.  Also this year, BMC was a sponsor/exhibitor.  This gave us a chance to set up a table displaying some mirrors and information about our products and technology. It was in a great spot at the conference where lunch, coffee breaks and the Tuesday night reception were held. While the conference was not as big as some other SPIE events (e.g. Photonics West and Optics and Photonics), it was a great opportunity to meet with some key people.

A couple of takeaways from the meeting were

(1)    NASA SBIR/STTR program is strong and growing. 

They are using the research funding they have for strategic programs that will help with technology development, which was called out in the decadal survey  as an, if not the, important push for the next ten years.

(2)    There is a continuing need for BMC mirror technology. 

There are a number of projects that will require the wavefront control that our DMs can provide.

Both of these items point to a rich future for BMC and the deformable mirror industry as a whole. We look forward to connecting with these folks again next year and for many years to come.

 

Dr. Meng Cui of HHMI Discusses Deep Tissue Microscopy Technique

Posted by Michael Feinberg on Wed, Aug 01, 2012 @ 02:39 PM

Tags: deformable mirror, adaptive optics, biological imaging, deep tissue microscopy, Howard Hughes Medical Institute, Janelia Farm Research Campus

hhmi logo

Our customers are constantly making exciting scientific discoveries and we’re proud of the part our deformable mirrors play in their research. Dr. Meng Cui, Lab Head at Howard Hughes Medical Institute, Janelia Farm Research Campus recently presented the Iterative MultiphotonAdvanced in Biological Photnics Adaptive Compensation Technique (IMPACT) that his team has developed for deep tissue microscopy at a webinar on “Advances in Biomedical Photonics”.  In Dr. Cui’s presentation he discussed IMPACT which utilizes iterative feedback and the nonlinearity of two-photon signals to measure and compensate wavefront distortion introduced in tissue.  He gave details on the imaging results on a variety of biological tissue including brain tissue through mouse skull and labeled  T cells inside lymph nodes and compared his team's technique with conventional adaptive optics methods.   For more details on Dr. Cui’s research you can view the entire webinar which was presented by Photonics Media at http://www.photonics.com/Webinar.aspx?WebinarID=21.  Details of the research can be downloaded from the following site: http://www.pnas.org/content/early/2012/05/09/1119590109.full.pdf