Photon counting, addendum
Let me add some clarification to the hybrid PMT post.
The actual signal that comes off of a PMT in response to a photon is a pulse of current….
Search Results for "two photon"
PMTs for 2-photon imaging
Posted in Hardware
On the topic of custom two-photon imaging rigs, what kind of PMTs do you want to go with? Naturally, you’ll order yours to be hand selected for high quantum efficiency and low…
Building a 2-photon microscope
Posted in Hardware
Less than a year ago, the patent on 2-photon microscopy ran expired (Nov 14, 2009 pdf). So now anyone can sell a kit or system for two photon microscopy without having to pay a licensing fee.
If you don’t want to start from scratch, there are a lot of options.
Prairie Technologies
Lasers for multiphoton microscopy
Posted in Hardware
Coherent just sold its 1000th Chameleon system. That’s roughly how many of the similarly-priced Lamborghini Countach LP500s were sold. That was in the 1980s. Coherent has been selling Chameleons since…
A fantastic shroud for visual stimulation during imaging
Posted in Uncategorized
In two photon imaging, we want the detector (photomultiplier / PMT, or SiPM) to see only the green photons from the fluorescent molecules we’re interested in (e.g., …
Real-time tracking and 2p imaging with sub-ms timing
Posted in Papers
In this work, the authors used fast optical motion tracking and 2p imaging to measure the activity of individual neurons in freely moving animals. No surgery. No optical window. No restraint. And all the benefits…
Meyer Navigator for ScanImage
Posted in Software
Software from Stephan Meyer Zum Alten (Gilbert lab, Rockefeller):
I put together a sort of Navigator for Janelia Farms ScanImage Two Photon control software, which we use a lot in our lab. There was no way…
Pulsed laser power part 2
Posted in Tips
In a previous post, we discussed how peak power is computed. Although Ti:Sapph laser manufacturers typically quote the average power, peak power is the more relevant quantity for two photon excitation. Here’s a graph showing…
Scientifica’s 2p scope
With its newly introduced scan head, Scientifica’s 2p scope is finally a complete package. They’re happy to sell their modular design in pieces, so this fills the void between fully custom rigs and turnkey…
Z-Projections
To project 3D image stacks to a 2D image, several different algortithms can be used. Maximum projections and averages are the most commonly used. Neither of…
Software for custom 2p scopes
Posted in Software
If you build your own two photon scope, you’ll need software. I mainly use the MATLAB-based ScanImage. Vijay Iyer (Janelia Farm) has really made it a slick, stable program. It cosmetically resembles Tom…
Options for pulse compression for 2p imaging
Posted in Uncategorized
Shorter pulses have greater bandwidth.
This topic came up on social media and I’ll jot a few notes here in case it might be useful for others.
I posted about this a year ago, but it was about when you need a prechirper. I’ll elaborate on what kind…
Neuroscience with particle physics level confidence
Posted in Uncategorized
PART 1. Our tools are imperfect. When I first got into neuroscience, I started deep down into neural circuitry: individual neurons and synapses. It was exciting to get …
Guidance for designing an objective from scratch
Several people have reached out for guidance on designing and building an objective from scratch, when they have little-to-no background in custom optics. Here are some notes on the topic, in broad strokes, focused on the practicalities.
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Open, easy laser-scanning microscope software: LSMAQ
Posted in Software
Years ago, Benjamin Judkewitz wanted to try some new techniques out with laser scanning two-photon microscopy. However, the software we were using was rather cumbersome to modify. So he wrote his own software from…