Optics
Theory :
Collimated light to determine focal length
Lesson on all photonic microscopy techniques and holographic two photon microscopy
Whole devices :
Holographic screens : Le Looking Glass portrait
Parallax Barrier : how to make a "3D" display without glasses
Building Laser :
Instructables schema from laser diode
Discussion on UV curing glues and UV lamps related
Microscopes :
Multi photon :
custom access serial holography :
Explanation of Walther Akeman's holographic microscope in french
Active components :
AOM/AOD :
AOM (acousto optic modulators) :
An acousto-optic modulator (AOM), also called a Bragg cell or an acousto-optic deflector (AOD), uses the acousto-optic effect to diffract and shift the frequency of light using sound waves (usually at radio-frequency).
AOD (acousto optic deflectors) :
An acousto-optic deflector (AOD) spatially controls the optical beam. In the operation of an acousto-optic deflector the power driving the acoustic transducer is kept on, at a constant level, while the acoustic frequency is varied to deflect the beam to different angular positions.
Photosensitive devices :
Measuring their performance :
Cathode radiant sensitivity :
The responsivity of a cathode to radiation, defined as the ratio of the current transmitted by the photocathode to the incident radiant power of a specific wavelength.
Cameras :
Calculator for working distance, working area, and focal length : https://www.flir.fr/iis/machine-vision/lens-calculator/
Embeded cards and cameras for AI live work - Built aroung NVIDIA Jetson nano
Board cameras : often use m12 mount (like raspberry pi ones) also called S mount (or board lens mount, or CCTV lens mount)
C-Mount (classic for industrial cameras)
RMS thread mount (for microscope planapo objectives) - From the royal microscopical society...
Focal distance adaptation :
Tutorial n°1 site web
Tutorial n°2 video youtube
Tutoriel n°3 video youtube
HyperSpectralImaging (more than 3 spectral lengths)
Linear Arrays :
Hamamatsu comparative (up to 46 pixels) designed for spectroscopy
InGaAs PIN photodiode array : G12430-046D : -46-element array - Large photosensitive area size
PhotoMultipler tube (PMT) :
MicroPMTs as mammamatsu for embeded two photon microscopes.
Passive components :
Astigmatism (optical) :
An optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci.
Optic Fibers
SCHOTT Fused Imaging Fiber Optics can be designed to magnify, minify, invert or simply transfer an original image to anywhere needed for defense, medical, and industrial applications.
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Based on light mode wich is the orientation of oscilation of magnetic and eletric (H and E) fields regarding the direction of travel of the wave. It's analoguous to mechanical systems normal modes.
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Transmision is limited in length by modal dispersion (about 940 meters)
It simply is a wave guide where the index of the optical core and coating make light undergo total internal reflection, if entering below an acceptance angle (wich value derivates to the number of aperture of the fiber)
In fiber-optic communication, a single-mode optical fiber (SMF), also known as fundamental- or mono-mode,[1] is an optical fiber designed to carry only a single mode of light - the transverse mode.
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No degradation of signal
Low dispersion
Well suited for long distance communication
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Manufacturing and handling is more difficult
Higher price
Coupling light into the fiber is difficult
Fundamental modes :
The lowest order mode of a waveguide.
Ttransverse modes (or lateral modes). are fundamental modes.
The fundamental mode of a waveguide is the one with the highest effective refractive index.
Basically, all modes other than the fundamental are higher order modes.
Not all waveguides support higher-order modes, at least not within their guided modes; they are then called single-mode waveguides
Higher-order modes are more susceptible to attenuation in wave guides. They are also more sensitive to bending loss.
Better for light throughput at lower distances (like LED or lamp launch condition, overfilled.)
A physical path taken by a signal or signal component that is either parallel to or relatively modestly transverse to the waveguide. Some signal components travel directly through the center of the waveguide, at least theoretically, and, therefore, travel the shortest possible distance between the point at which they enter the waveguide and the point at which they exit the waveguide. They are the one that occur more with an underfilled launch condition (laser input) better for light throughput at long distances (>10/20m). Less sensitive to bending loss and attenuation.
Image transmission with multimode fibers :
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10417
https://yelin.net.technion.ac.il/files/2015/10/Image-transmission-through-fiber.pdf
https://www.nature.com/articles/s41467-019-10057-8
Lenses :
Advantages of an infinity corrected optical system
Refractive Lenses :
Lens quality and many interesting notions on camera lenses :
- Moulded & Ground Lenses
- Bokeh
Photographic lens designs :
- Planar
- Tessar
- Sonnar
- Spheric and aspherical lenses
- Achromatic doublets (achromat, apochromat, superachromat)
Catadioptric / reflective lenses :
Catadioptric system was often used in the 70-80s for telephoto lenses. Advantages and invonvenients :
Advantages : Lightweight , less expensive, no chromatic aberration
Disadvantages : donut bokeh (can be an advantage as it is quite artistic), fixed aperture and focal length, vignetting, low contrast
Make image at infinity (to use with infinity-corrected objectives that are a standard for modern microscopes manufacturers)
Prisms:
- Wedge Prisms : a set of 2 can allow for 2D displacement of a light ray(can be both used for projecting or reading with an adjustable FOV camera) if both are rotatively controlled.
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Dove prisms are able to retroreflect (and invert) image or rotate the image by twice the angle applied to the prism relative to the image source orientation. http://ishikawa-vision.org/vision/rollcamera/index-e.html
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Risley Prism Beam (RPUPS - universal pointing system) ( based on wedge prisms )
Anti reflective coating to reduce reflected light - works in specific wavelength ranges usually
Suppliers :
Semrock (brightline
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Chroma filters
Optoprim
Edmund optics
Throlabs
Andover corporation
Bibliography :
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Edmund Optics : Light polarization technique