Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [optics]

Anything related to optics applied to electronics. Optics is a branch of physics studying the properties of light and its interactions with physical media.

Anything related to optics applied to electronics. Optics is a branch of physics studying the properties of light and its interactions with physical media.

See also Wikipedia on optics.

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How does a laser printer control the laser to produce such high resolutions?

I opened up a broken laser printer yesterday to find one of the important sections (this is an example photo from Google Images), trying to learn from the design of the laser+polygon mirror motor within: I was able to find the pinout of the driver…
sasha
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Why are most COB LEDs physically yellow?

Many "LEDs" found on devices nowadays appear to be yellow where the light comes from (when the device is off). Why yellow? I put LEDs in quotes because COB leds can consist of many individual LEDs in an array/grid. In my example photo below, you can…
Bort
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Can an optical mouse be used to measure distance down to 1-10μm?

I am working on a home-built CNC machine that uses stepper motors and MXL timing belt for the machine movement. Because I'm using steppers, there is no feedback to the controller about the actual position of the machine (ie, open-loop). Sometimes…
dext0rb
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How is lithography actually used to "print" transistors?

In one of my classes, we skimmed over lithography, but mostly the optics side of things (the diffraction limit, liquid immersion to increase angle of incidence, etc). One point that was never covered is how the light actually dopes the silicon, and…
Jay Greco
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What is the technical difference between audio CD-R(W) and data CD-R(W) discs?

I just repaired a Sony RCD-W100 CD-recorder and want to test the recorder functionality. The manual 'says' I can only use audio CD-R(W) discs. Never heard of CD-R(W) discs just for audio. On the computer, it is possible to make audio discs with…
Codebeat
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What are the tradeoffs for the various options coupling a LED to an optical fiber?

I'm trying to couple a white LED to a fiber bundle that's comprised of several 30 uM silica fibers. The bundle outer diameter is on the order of .5 mm. The NA of the fiber is .87 and the whole bundle is placed in a stainless steel ferrule that's…
Doov
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Is birefringence exploited or otherwise meaningfully observed anywhere in electronics?

Birefringence is a property of certain materials where the refractive index of the material is dependent upon the polarization and direction of propagation of light through it. I recently learned about it while reading a book on lasers. Reflection…
Polynomial
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Optical heart rate sensor vs bioimpedance sensor?

I didn't know a better place to ask this, so here it goes. For activity trackers, Fitbit has the Charge HR with an optical heart rate monitor, while Jawbone has the UP3 with a bioimpedance sensor for heart rate. Can you please explain the…
adamaero
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Measuring pulse durations with microsecond precision or better

Problem I'll be receiving pulses and want to know the relative times of pulse start/end with microsecond precision (or better). Pulse characteristics: pulse frequency: probably 1Hz to 10Hz pulse length: 1μs to 200ms pulse spacing: >10μs between…
Mark K Cowan
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Understanding optical parameters of image sensors

I noticed that image sensor manufacturers provide some optical characteristics in different formats. I wish to know how to interpret that information. Sensitivity is characterized in \$\dfrac{V}{lx \cdot s}\$ for S11639 and TCD1201, which is…
Nazar
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Is it feasible to use fiber optics to increase the detection area of an infrared photodetector array?

I'm working with an infrared emitter/detector system based on an Osram SFH 4545 IR LED collimated through a 40mm dia, 120mm fl lens and a sensor array based on three separate sets of three Vishay TSOP 34856's all running a 56kHz signal. Both…
Rampant Mongoose
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How to calibrate an optical particle sensor (Mie scattering)

I have a very simple sensor that basically emits infrared light (1 micron wavelength in the infrared range). The light scatters off particles whose diameter is of the same order of magnitude as the wavelength (Mie scattering). The scattering angle…
l3win
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Why is the frequency response of an LED important?

I'm working on visible light communication where I fabricate my own organic LEDs. One of the ways to characterize them is "small signal analysis." I understand we are applying this analysis to see the bandwidth of the OLED, but I do not understand…
LifeIsBeatiful
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Are optical fibers full duplex?

Can optical fibers transmit in both directions simultaneously? Both single mode fibers and multi mode? What about if they we choose non-interfering wavelengths?
Jader Dias
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ambient light rejection in absorbance sensor

I'm making a sensor to measure light absorbance in a sample where the geometry varies over time. I found a very nice transimpedance amplifier, the AD8304 designed for use with PIN photodiodes with a nice and wide dynamic range and logarithmic…
Ben Voigt
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