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hardware:lasers [2016/03/04 00:51]
Jon Daniels [Getting Dual Outputs] |
hardware:lasers [2024/02/12 22:57] (current)
Jon Daniels [Oxxius Laser Combiner] |
| Various laser launches can be used with diSPIM. Below find notes specific to each one. | Various laser launches can be used with diSPIM. Below find notes specific to each one. |
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| In normal diSPIM use the laser launch will be controlled using its digital TTL inputs. The Tiger controller's PLC card will be generating those signals, which will turn the lasers on/off at the appropriate times and selecting the correct side. For information on connecting the cables see the appropriate [[:docs:manual#connecting_cables | section of the manual]]. The analog intensity is generally static during the experiment and so can be controlled using the high-level software (Micro-Manager or vendor's software) over a USB or serial connection; there may be some enabling that needs to happen using the high-level software. If analog intensity must be controlled during an experiment then ASI can provide a separate Tiger card which can drive the laser's analog inputs. | In normal diSPIM use the laser launch is controlled using digital TTL inputs. The Tiger controller's PLC card generates those signals, which will turn the lasers on/off at the appropriate times and also selects the correct side if needed. For information on connecting the cables see the appropriate [[:docs:manual#connecting_cables | section of the manual]]. The analog intensity is generally static during the experiment and so can be controlled using the high-level software (Micro-Manager or vendor's software) over a USB or serial connection; there may be some enabling that needs to happen using the high-level software. If analog intensity must be controlled during an experiment then ASI can provide a separate Tiger card which can drive the laser's analog inputs. |
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| | In general the laser power requirements are very modest, e.g. a few mW of optical power at the sample at most and often less than 1 mW for live imaging where phototoxicity is a real problem. The exact power required depends on the sample (fluorophore density, efficiency, required SNR and readout speed to get the biological answers you're seeking). Light sheet microscopy is particularly efficient with excitationlight, but every sample will bleach eventually so the intensity is often increased to improve SNR until bleaching becomes problematic. |
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| | Often the laser launch is the most expensive part of the light sheet microscope system, so if you are looking to save money then start by looking here. It is possible to assemble your own laser combiner; see e.g. the [[https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173879|"Nicolase" combiner]]. |
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| | The ASI scanner has a fiber optic input with either an FC/PC or FC/APC connector (specify which when ordering). The focal length of the collimation lens should match the fiber's NA to fill the scanning mirror appropriately, for NA ~0.11 the default 12.5 mm focal length lens works well and for NA ~0.06 order the 20 mm focal length option. Single-mode fiber is required for intended operation. |
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| In general the laser power requirements are very modest, e.g. you only want at most a few mW of optical power at the sample. So no need to pay for lasers with extra power. | |
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| ===== Getting Dual Outputs ===== | ===== Getting Dual Outputs ===== |
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| For a dual-view system it is helpful to have a laser launch with dual outputs. That way the entire laser intensity can be switched between the two paths since only one path is used at a time. Such launches are not common but multiple options are commercially available (see below). | For a dual-view system it is required to have a laser launch with dual outputs. Such launches are not common but multiple options are commercially available (see below). |
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| If you don't use a laser launch with dual outputs you have two basic approaches: (1) split the beam passively or (2) insert an active switch. | If you don't use a laser launch with dual outputs you have two basic approaches: (1) split the beam passively or (2) insert an active switch. |
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| First, you can passively split the beam into two fibers and rely on the unused scanner to blank its beam at any given point in time. The scanner gives decent but incomplete blanking (up to 0.1% bleed-through). Fiber splitters are inexpensive and compact but the split ratio depends on wavelength so this doesn't work for multi color. You can split into 2 paths in free space on an optical table before fiber coupling, which requires some expertise but allows a 50/50 split across wavelengths. ((this was done on the original diSPIM, see Supplementary "Note 1 SF2, Excitation laser launch for diSPIM" in [[http://www.nature.com/nprot/journal/v9/n11/extref/nprot.2014.172-S1.pdf|Supplementary Notes]] to the Nature Protocols paper)) When using an optical table it's possible to insert shutters to fully block the beam. ASI is prototyping a compact self-contained beamsplitter. Passively splitting the beam reduces the intensity by at least a factor of 2 (more with losses) but normally that isn't a problem because light sheet imaging usually uses very low intensities. | First, you can passively split the beam into two fibers and rely on the unused scanner to blank its beam at any given point in time. The scanner gives decent but incomplete blanking (up to 0.1% bleed-through, which is normally acceptable because when acquisition isn't happened the laser is off anyway). Fiber splitters are inexpensive and compact but the split ratio depends on wavelength so this doesn't work for multi color. You can split into 2 paths in free space on an optical table before fiber coupling, which requires some expertise but allows a 50/50 split across wavelengths. ((this was done on the original diSPIM, see Supplementary "Note 1 SF2, Excitation laser launch for diSPIM" in [[http://www.nature.com/nprot/journal/v9/n11/extref/nprot.2014.172-S1.pdf|Supplementary Notes]] to the Nature Protocols paper)) When using an optical table it's possible to insert shutters to fully block the beam. Passively splitting the beam reduces the intensity by at least a factor of 2 (more with losses) but normally that isn't a problem because light sheet imaging usually uses very low intensities. If slit scanning is implemented (not in Micro-manager as of May 2016) there is a possibility of ~2x speedup in acquisition by simultaneously imaging from both sides with a slight offset in beam position, and this potential speedup will require a split beam as both scanners will be illuminating simultaneously. |
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| Second, you can add a galvo or 1x2 switch between the laser output and the two scanners. Leoni makes a commercial switch with male fiber inputs and outputs. You will need to couple the laser's fiber with the switch's input fiber, e.g. with a butt-coupler and its attendant losses and possible degradation over time. You could also find a vendor to do fiber splicing. Another option is to to free-space switching using a galvo or similar on an optical table. There may be other switching options available, if you know of one please add it to this wiki! Active switching usually involves some loss but generally speaking you can keep more than 50% of the input intensity. | Second, you can add a galvo or 1x2 switch between the laser output and the two scanners. Leoni makes a commercial switch with male fiber inputs and outputs that ASI can source. You will need to couple the laser's fiber with the switch's input fiber, e.g. with a butt-coupler and its attendant losses (e.g. 90%) and possible degradation of the fiber tips over time.((supposedly most problematic with ongoing use of UV wavelengths e.g. 405 nm which can interact with volatile compounds and deposit them on the surface)) Note that you should only butt-couple similar fiber terminations, either FC/PC with FC/PC or FC/APC with FC/APC so take care to order the same termination on the Leoni switch as your laser launch has. You could also find a vendor to do fiber splicing to the switch. Another option is to to free-space switching using a galvo or similar on an optical table. There may be other switching options available, if you know of one please add it to this wiki! Active switching usually involves some loss but generally speaking you can keep more than 50% of the input intensity. |
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| ===== Laser Launches Used with diSPIM ===== | ===== Laser Launches Used with diSPIM ===== |
| ==== Toptica MLE ==== | ==== Toptica MLE ==== |
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| [[http://www.toptica.com/products/multi_color_systems/ichrome_multi_laser_engine_l.html | Vendor's brochure for MLE-L]]. | [[http://www.toptica.com/products/multi-laser-engines/ichrome-mle/ | Vendor's brochure for MLE-L]]. |
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| === Implementation notes === | === Implementation notes === |
| * Special dual-output version available on request | * dual-output version (integrated switch) available |
| * choice of multiple laser lines installed at factory | * choice of multiple laser lines installed at factory |
| * automatic alignment feature makes setup easy even after shipping | * automatic alignment feature makes setup easy even after shipping |
| * very compact form factor compared to other launches | * compact form factor |
| * fibers have NA ~0.06 | * fibers have NA ~0.06 |
| * 50 ohm SMB inputs for each laser on/off, version with switch has high impedance BNC input for fiber select built into interlock cable | * 50 ohm SMB inputs for each laser on/off, version with switch has high impedance BNC input for fiber select built into interlock cable |
| === Micro-manager notes === | === Micro-manager notes === |
| * Use Toptica MLE device adapter. Fairly full-featured and supported by Toptica. | * Use Toptica MLE device adapter. Fairly full-featured and supported by Toptica. |
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| | ==== Vortran VersaLase ==== |
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| | [[http://www.vortranlaser.com/index.php/products-main/stradus-versalase-multiple-wavelength-modules.html | Vendor's brochure for VersaLase]]. |
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| | === Implementation notes === |
| | * choice of multiple laser lines installed at factory |
| | * compact form factor |
| | * 50 ohm SMB inputs for each laser on/off |
| | * integrated switch/split not yet available but being developed |
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| | === Micro-manager notes === |
| | * Use Vortran VersaLase device adapter. Hardware changes to the launch (circa 2021?) prevent using Micro-Manager with the latest launches as of Oct 2023. Vortran is aware of the problem; the more customers ask the more likely they will be to allocate resources to fix things. In the interim you can use an analog output device controlled via Micro-Manager (e.g. ASI's TGDAC4 card, Triggerscope, etc.) to control the laser intensity so that the intensity settings are saved in the image metadata. |
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| ==== Spectral Applied ILE ==== | ==== Spectral Applied ILE ==== |
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| (no info seems to be available online but similar to LLM5 with dual output option) | (no info seems to be available online but similar to LLM5 with dual output option; Spectral Applied was purchased by Andor but I think the launch is still available from them) |
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| === Implementation notes === | === Implementation notes === |
| === Micro-manager notes === | === Micro-manager notes === |
| * Use OBIS device adapter (not maintained by manufacturer) | * Use OBIS device adapter (not maintained by manufacturer) |
| * As of Nov 2015, device adapter only works with single-line OBIS; with the multi-line box only the laser in the first position can be controlled | * As of Nov 2015, device adapter only works with single-line OBIS; with the multi-line box only the laser in the first position can be controlled so get a single "remote" controller for each laser line |
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| | ==== Oxxius Laser Combiner ==== |
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| | === Implementation notes === |
| | * Dual output available, either switch or adjustable splitter (both fibers simultaneously) |
| | * Many features and wavelengths available |
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| | === Usage === |
| | * Make sure you place the fiber coupler on its correct magnetic base. Otherwise you can have significant power loss. |
| | === Micro-manager notes === |
| | * The combiner must be set up as a virtual comm port. Use the "CDC" command. (https://micro-manager.org/Oxxius_combiner) |
| | *It is recommended that you include, emission, shutters, and digital modulation in the startup group. |
