Questions tagged [optics]

Optics is a branch of physics describing the behaviors and properties of light (electromagnetic waves). Questions regarding the properties of light, it's interactions with matter and the instruments used to detect and deflect (or concentrate) light should be posted here.

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8 votes
1 answer
145 views

How can I estimate blocking window distance in an sCMOS sensor setup?

I am trying to establish an appropriate distance between a spectrograph output window and a CMOS sensor. The spectrograph creates a focused image on the CMOS sensor but I am trying to restrict the ...
0 votes
0 answers
26 views

Lens arrangement for laser tag?

I’m working on a laser tag game using IR LEDs and demodulation ICs. The trick is to force the gun to be aimed accurately at the center of the target. I’m willing to experiment, but I don’t really know ...
0 votes
1 answer
75 views

Prototyping optics for laser rangefinder

I am a software engineer dabbling in optoelectronic systems. I can bumble my way through but I don't really know what I'm doing, and right now I'm figuring out how to prototype optical components. The ...
1 vote
0 answers
48 views

Red Laser Safety Filters?

First of all, apologies if this is the wrong SE site. Last year I bought a k40 laser cutter and it came with a square orange/red acrylic safety filter, which is meant to be used for looking through ...
1 vote
0 answers
15 views

Identifying and replacing a lens of a 360° Giroptic camera (360cam) [migrated]

I broke a lens of a Giroptic 360cam. It is discontinued by the manufacturer and even the company does not exist anymore. Here is a link from the internet archive. All the tech specs I found is those: ...
0 votes
2 answers
48 views

How to solve transient heat conduction equation at a point in space with volumetric heat source?

My system is a fluid exposed to light and I want to calculate the temperature change with time at a point, hence there are no spatial effects or convection due to the flow of the fluid. The heat ...
0 votes
0 answers
16 views

How to filter out light entering bayes filter

I am trying to run an experiment where I have green fluorescent beads that absorb 490nm light and when excited, emit light at 515nm. Right next to it, I have brilliant blue light that absorbs ~620nm ...
0 votes
1 answer
30 views

What are the effects of temperature on optical fiber waveform

I am attempting to measure temperature using a signal through an optical fiber. If I send a waveform through an optical fiber, how would temperature affect it? I've looked here (Calculating ...
0 votes
1 answer
62 views

Diffusing a Laser beam

I am working with a variable power laser system that has a wavelength of 0.8μm – 1.1 μm. The laser set up in the lab must be able to weld any gauge of material together for the experiment to take ...
1 vote
1 answer
54 views

How is light guided by a perfect mirror waveguide for angles not exactly at the guided mode angles?

Take the below image for example: Let's imagine the cladding is really just perfect mirrors, where all light energy is reflected back towards the core. I understand that modes arise by imposing the ...
0 votes
0 answers
11 views

Mounting APC E-2000 fibre terminator to Thorlabs parts

I am building an optical setup that consists of Thorlabs parts. The laser for the system has a pigtail that uses an APC E-2000 fibre terminator type. Thorlabs does not sell any compatible parts for ...
0 votes
1 answer
84 views

What is the branch of engineering that deals with corrective eyeglasses?

So I was curious about what principle used to manufacture corrective eyeglasses. Of course it uses physics, especially optics. But what engineer branch or degree is needed to manufacture it? I ...
2 votes
1 answer
205 views

What is the optical Lagrange invariant of an afocal system?

I am solving an optics exercise that requires to design a Keplerian telescope with a given magnification M (negative), a certain object size L and the restriction of not having lenses faster than F/1 (...
0 votes
3 answers
487 views

galvo scanner + rotating off-axis mirror for beam offseting?

diagram: Assuming 1) the scanner can angle a beam anywhere on the circular off-axis mirror and 2) the off-axis mirror can be rotated as an the diagram to any angle needed, can the beam shooting ...
1 vote
1 answer
62 views

Passive Infrared Sensors (PIR) spectrum and reflections

I have a common PIR occupancy sensor (Lutron MS-OPS5M-WH). I am trying to get the sensor to cover an irregular-shaped room. I could expand the field-of-view of the sensor to cover the whole room by ...
0 votes
0 answers
38 views

Optical diffuser design

I have a small 3D printed SLA box, about 3.5" x 2.5" x 2". Here is the bottom half: And the top half with an LED inside, facing down, placed off-center, about 1.75" above the &...
1 vote
1 answer
59 views

Which optical filter to use for flat black non-glare aerospace indicator?

I am currently designing a LED light indicator for use in an aircraft cockpit replica. I’m asking for expert advice on the type of lenses to use in order to get a result similar to shown pictures. ...
2 votes
1 answer
81 views

How solid state lasers work?

In solid state lasers a light source pumps the medium, which is a crystal. A crystal is excited and emits infrared light, until then everything is clear. What I want to know: after excitement, what ...
1 vote
2 answers
136 views

How to digitalize a UV image (create an array of the light output at the pixel level)?

I would like to display an image onto a screen using a digital light projector and somehow record the amount of light the screen is receiving from each pixel. I have thought about using a visible ...
0 votes
0 answers
22 views

Make Multiple Displays Appear as One with Optics

I'm building a small information display using four 1.3" monochrome OLED modules positioned next to each other, powered by a microcontroller. I can configure these to act as a single display ...
10 votes
2 answers
3k views

Can a very bright light attract an incoming laser guided weapon?

I would like to know if a very bright light will attract an incoming laser guided weapon such as a laser guided missile. Say for example that a tank has a six-foot pole on the top of it and attached ...
0 votes
0 answers
26 views

Bandwidth distance product formula

I read the following in one reference: A copper wire (twisted pair), the link traditionally associated with low bit rate transmission, is still in use in the modern data centers transmitting data at ...
0 votes
1 answer
41 views

Plus and minus power of Cylinder

This is my glasses prescription, is the cylinder minus applied at the meridians 180 and 10? So the the light is diverged at 180 and 10? Or does the axis value refer to the horizontal axis of a ...
-1 votes
2 answers
57 views

Angle of incidence in concave mirrors [closed]

What happens when you change the angle of incidence(normal to the mirror)? How does the angle of reflection change? Is it invariant?
1 vote
2 answers
80 views

Dioptres of lens in glasses

If your glasses lenses have a +2.00D SPH and -1.75CYL. Does this mean the lens is composed of both cylindrical lenses and spherical lenses? For the Spherical lenses, if the diopetres is 2. The focal ...
0 votes
0 answers
26 views

Determining the irradiance from radiant intensity and radiant flux

I am working with an LED spec sheet and would like to calculate the irradiance vs the viewing angle. The relevant data given is the following: Radiant Flux: $\Phi_{e} = 1930 mW$ A relative radiant ...
4 votes
2 answers
2k views

Why does light bend after travelling half of the lens?

As light enters a denser medium from a rarer medium, it bends towards the normal. Why does the light bend after passing through point F & not E?
0 votes
0 answers
17 views

Choice of lens for enlarging an image? Building a custom camera back

I'm investigating the feasibility of building an adapter for my medium format film camera to shoot Polaroid film. The normal film back for the camera uses 120 film, where on each shot a 60x40mm frame ...
3 votes
1 answer
98 views

Differential Equation for: Locking a laser's frequency with a PI controller

I think I have a good understanding of differential equations, so I would like to first try to understand my system in terms of differential equations before transforming my system into the more ...
0 votes
0 answers
17 views

How can I visualize the phenomenon of Bound State in Continuum?

I am doing my Masters Thesis on Bound States in Continuum (BIC) and I am finding it difficult to visualize the concept. Is it possible to observe the phenomenon through an FDTD simulation? It is also ...
0 votes
0 answers
20 views

Please help to understand relation between simplified and real optical system for triangulation process

I'm far away from being an optical engineer, so I require some assistance. I have an optical system consisting of industrial camera and lens (manual iris + manual focus). 1)Lens documentation states ...
0 votes
0 answers
41 views

Determining an adequate lens for collimation

I'm looking to develop an optical system to collimate a LED that is going to be fitted to glasses. I have a 5 mm diameter de-domed LED with a circular aperture that I need to produce a clean and even ...
1 vote
1 answer
30 views

Why does my wall reflect green color when I shine blue light on it?

On the wall , i Walter had put a poster & when I removed the poster. I shone blue + red + white light on my white wall in the dark room. Under blue light only , I am able to see so many details. ...
0 votes
0 answers
56 views

How can a screen be projected on a transparent glass?

I am building something similar to Google Glasses although not exactly that. I am trying to find a way to project my 0.96inch OLED on a glass, but it can't block the front view. What I tried to do is ...
1 vote
2 answers
121 views

What's the difference between pulsed lasers and frequency combs?

Can you please explain the difference between high-energy pulsed lasers and frequency combs?
2 votes
1 answer
142 views

How can a small screen be projected on glass but still visible near 2cm from eyes?

In the smart glasses the images are projected on glass. But they are still clear to eyes. We usually can't see something clearly at such close distance. Then, how is the image projected from a small ...
0 votes
0 answers
30 views

Optics: imaging a plane of a water spray/jet

I'm trying to think through a new experimental set-up, involving a sheet of water being shot up over a step structure. The water sheet will be about 5" wide, and the camera will be positioned ...
1 vote
3 answers
103 views

Calculating Temperature of an Optical Fiber

Let's say there is 30W of light pumping into the fiber. Parameters: Length of Fiber: 6cm Input - 30 W Output -29W Loss of 1W The diameter of optical fiber is 0.25mm. Since the optical fiber is ...
1 vote
1 answer
71 views

Heat loss in Optical Fiber

I am conducting a thermal analysis of optical fibers. ( Software used AutoCAD Fusion 360) The Inputs conditions are : Let's assume an input power of 1250W, with an efficiency of 98%. 2% loss which ...
0 votes
0 answers
17 views

In-line holographic imaging: phase retrieval vs image reconstruction

I'm trying to understand holographic microscopy but I am getting very confused with the terms and methods involved. From what I understand in holographic imaging is that we can use the below integrals ...
2 votes
0 answers
43 views

Comparison of beam divergence between laser diode and DPSS laser

I'm currently comparing a pulsed laser diode and a pulsed DPSS laser. For the DPSS laser, the beam divergence is listed as "beam divergence (80% of total energy): $<4 \text{mr}$". The ...
2 votes
2 answers
580 views

Does this type of lens or light guide exist?

I am trying to create a line made from light projected from a lens / guide of some sort onto a surface from a few mm away. I have used a laser, but comes with safety considerations, space to mount the ...
4 votes
1 answer
473 views

Alternatives to laser line?

I'm trying to project a very thin line at a low angle over some surface defects (peaks and troughs). The scale is ~20mm square, but the defects can be sub-mm (0.2 - 1.0mm). I am currently using a line ...
1 vote
0 answers
35 views

How to multiplex several light sources into one optical path?

I'd like to design a device that takes 4 channels of light from sets of LEDs and multiplexes them into one optical path, which finally creates a rectangle pattern of light that is approximately 30mm ...
1 vote
0 answers
22 views

Spectrometer design

I am looking to design a compact spectrometer based on using one single concave grating as both the dispersive optic and the imaging optic. I am investigating these gratings: https://www.edmundoptics....
2 votes
2 answers
101 views

Using phone screen as a barcode

I have this extremely minor problem where my gym is 4 blocks away, and I'd like to go over with nothing but my phone. Unfortunately, I have to bring a card with me for them to scan with a barcode ...
0 votes
2 answers
85 views

What is this part of a camera called?

Some cameras have a pattern similar to stairs close to their lens. For example: Such a system absorbs and/or reflects undesired light rays in order to improve image quality. How would you call such ...
0 votes
0 answers
22 views

Floating node in 4T CMOS camera pixel

I know how a 3 Transistor CMOS camera pixel works. As I understand, 4T CMOS pixels have one additional transistor that connects the photodiode to a so-called floating node. What is that floating node ...
2 votes
0 answers
30 views

Home made microscope using donated objective lens and camera-ocular-adapter

I have a bunch of nice objective lenses from an huge old microscope set, and would like to make a microscope body tube with just one objective and one ocular lens. Without using trial and error to ...
0 votes
1 answer
56 views

45 Degree Coupler on Fibre Optic cables

I was reading through a research paper and they showed the following schematic: I am not exactly sure what is meant by a 45 degree coupler so I looked online but there is no such thing as a 45 degree ...