# Questions tagged [photonics]

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### How to approach photonics related research works?

I am a student in sophomore year in a college pursuing electrical and electronics engineering. My college offers chance to major in any of the 3 sectors of this department which are: 1)Electronics and ...
• 101
36 views

### Can air be implemented in 1-Dimensional photonic crystals?

As far as I am aware, digging holes in nanostructures or using columns of materials in a medium of air is the main way by which 2D photonic crystals work. I thought it would also be common to ...
26 views

### Where can I get a 4.26µm wavelength light source with variable intensity?

I want to conduct a small home experiment involving co2 particles detection. In order to do that I need a light source at 4.26µm wavelength (it's absorbed by co2 molecules), preferably with ...
• 101
53 views

### AutoCAD: Help with exporting micrometer details to PDF

I'm using AutoCAD and am trying to export a photolithography mask to a PDF file so it can be viewed and shown to others outside of the AutoCAD program. I'm having trouble with this, as whenever I ...
33 views

### Imaging base of HDR range

When speaking about HDR photography, do the magnitudes are measured in base 2 (stops) or base 10 (decibel)? I mean - what is the magnitude in linear scale of, for example, 100 dB HDR?
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1 vote
102 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 ...
1 vote
264 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 ...
• 129
1 vote
130 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 ...
• 129
60 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 ...
• 139
1 vote
47 views

### Calculate the temperature stability of wavelength demultiplexer

Hi ive been given this question: A wavelength demultiplexer (DMUX) used in a DWDM communication system has a channel spacing of 100 GHz. The operating pass band of each channel is 50 GHz. The ...
• 11
77 views

### What are some examples of laser-based additive manufacturing techniques?

I'm trying to research additive (or 'bottom-up') fabrication techniques that rely on lasers or other advanced photonic systems. So far, the most prevalent technique I've come across is two-photon ...
• 23
27 views

### How would measuring the number of photons on a finite number of pulses break coherence of a weak coherent laser source in COW QKD protocol

I' m trying to understand attacks on Quantum key distribution protocols. In the COW QKD protocol, pulses from Alice are passed through an asymmetric coupler and a fraction 'T' of the photons are sent ...
• 1
260 views

### LED Lumen Calculations

I am using an LED as a point source for a school project. I have two questions in regards to the LED(s). I know that light follows the inverse square law when measuring perceived brightness, but all ...
1 vote
258 views

### Epoxy that can withstand up to 800C and is optically transparent?

I'm looking to use an epoxy in a high-temp environment like 800C, and one that is optically transparent at 450nm (not below 90% transmission). But i'm having trouble finding one. It can be made of any ...
• 11
668 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 ...
• 205
188 views

### rotating mirror system for shifting a beam?

I am looking for some mirror setup where rotation one or more elements in the mirror setup will allow to shift the beam along its axis. Two mirrors in a galvanometer scanner type setup work well for ...
• 205
605 views

### how to implement autofocus for video projector

I have a modified pico video projector that I need to add an autofocus to. The focusing ring already has a fast stepper motor added to it. If the focus had to be done on the middle of the projection ...
• 205
1 vote
31 views

### Illumination properties of black lights

An elderly friend of mind whose eyesight is fading recently asked me if there was a way to illuminate her new induction stove top so that the "burner rings" would be easier to see, to her it just ...
173 views

### Is it possible to adapt the design and principle of operation for a tunable microwave photonic notch filter to a visible light photonic notch filter?

I just read the 2015 excellent paper , "Tunable microwave photonic notch filter based on sliced broadband optical source". Is it possible to downconvert a microwave photonic notch filter to a visible ...
• 179
1k views

### Can all electromagnetic spectra be focused like a laser?

Lasers have a wide range of applications, but can be very costly to produce at high power/intensity. Since light is nothing more than a narrow band of the electromagnetic spectrum, it makes me wonder ...
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