Optical Definition and 640 Threads

Hello Everybody, I am going to build an optical lab. to characterize semiconductors which have a luminescence over a wide range 200 nm - 1500 nm. I hope to have a setup which flexible to carry more than spectroscopic technique and be able to study this wide spectral range. I would...

Hi. I was wondering if someone can provide me with some advice on the proper way for measuring the optical power of a pulsed laser system? My optional methods are: - Photodiode detector: measuring average power - Oscilliscope with optic-electric converter...

hi friends I am going to buy optical chopper system for my work. But i need some clarification about system. If i want to chop say 2mm diameter of the beam, say it has of chopping frequency from 500Hz to 1000Hz. What is the difference if i chop at 500Hz and 900 Hz except the frequency...

Homework Statement 1. Peter cannot see distinctly objects closer than 40 cm from the eye. Find the power of lens that enable him to see objects at distinct vision 2. A man has near point of 50 cm and a far point of 200 cm. a. What kind of glass should he used to see normally? b. What are...

I'm having trouble understanding why only certain angles of propagation can transmit down an optical fibre. My lecturer produces this formula for the allowed angles: \sin \theta = p \frac{\lambda}{2dn} where \theta is the angle of the ray from the optical axis \lambda the wavelength of light d...

Homework Statement Pictures of an optical mouse I took apart are attached. We had to find a circuit, take a picture, draw the circuit diagram and explain how it works. I'm not sure what a few of the components are. U3 is for the scroll wheel but what is it? U1 (the big IC) is the guts of...

I was given the following question "An optical incremental encoder that produces 1,000 pulses per revolution is connected to the shaft of a motor. Determine the angular resolution of the encoder in degrees and the motor speed in RPM, if the encoder outputs 5,000 pulses in 1 second." I am...

As I studied, the optical branch of a crystal is called so because it can be excited with e.m. fields but I wondered whether it is possible to excite the optical branch also with chargeless particles like neutrons or the charge/action-on-charge is necessary for the process? And if so, why? I...

... your nose and down your throat? I had a throat ache that wouldn't go away, and so to see what was going on, they did this medical procedure. The interesting part is that I never saw it coming. They asked questions, cleaned away ear wax, sprayed a liquid in my nostrils, and out of no...

Hi everyone, I'm trying to gather some ideas of subjects for an oral presentation in my Optical Properties of Materials class: I'd love to find something pleasant or at least nice to develop (like I heard "how a cameleon changes color?"^^), not too theoretical if possible... And with some...

Hi, I'm a mechanical engineer that's new to optics. I'm trying to determine the best location to place an image sensor for an optical system with multiple lenses and mirrors. In doing so, I've come to the understanding that the best position to put the sensor is at the circle of least...

I was told that optical fiber communication market starts to recover. But I'm very frustrated in seeking an optical job here. Could anyone give some seeking hints? Many thanks.

Right now, I'm self-studying from J. J. Sakurai's book Modern Quantum Mechanics. In section 7.3, Optical Theorem, there is one step in the proof that he uses that escapes me. His proof involves using the transition operator T defined as: V \mid\psi^{(+)} \rangle = T \mid\phi \rangle \\...

Hi! I am new to these, and off the bat am confused by the units. Manufacturers quote resolution either in units of length, e.g. 0.04 nm, or HZ. For example, 0.04 pm / 5MHz 0.16 pm / 20 MHz 0.8 pm / 100 MHz. I am thrown by this since I thought frequency was the inverse of...

So i was messing around with a wax prism and a microwave emitter. So I have an emitter and a detector and the microwaves are being shot straight across to the detector. But when I place a Wax prism in between it stops getting the signal . But then when we place a second wax prism next to it, it...

Hi, I'm currently recalibrating an optical tweezer for my undergraduate thesis. The alignment did turn out well so far but I'm a little bit concerned about the power loss within the microscope (here's a picture of the relevant part, without prisms). I read in a paper that 20 to 100mW are...

Homework Statement A 3.1 cm--tall object is 26 cm to the left of a lens with a focal length of 13 cm. A second lens with a focal length of 8.0 cm is 42 cm to the right of the first lens. Homework Equations 1/s + 1/s' =1/f M=-s'/s and I'll have to multiply the two M's together to get the...

Let's say you have two pulses from the same source, one whose phase is slightly delayed relative to the other one. Now, I know that you can use an interferometer and a balanced detection-type scheme to measure the phase shift (in which case you can be shot-noise limited), but I'm wondering if...

hey guys! we know that velocity of a wave = wavelength x frequency. and speed of light changes with change in optical density. so there must be change in either frequency or wavelength or both. which of these quantities change with change in optical density? and why?

Homework Statement Homework Equations \frac{\delta{F}}{\delta{y}} - \frac{d}{dx}\frac{\delta{F}}{\delta{y'}} = 0The Attempt at a Solution I'm having trouble setting this one up. If I let the functional be F(x,x',y) = n(y)\sqrt{1+(x')^2} Applying the LE equation I obtain...

I know this very cool free software to create interactive geometry projects: http://www.geogebra.org/cms/ Does it exist any similar program which simulate how light rays move among mirrors and lens? If not, how can I simulate a lens in Geogebra? (a mirror is easy).

Which of the following materials have activity Optical ? i know it must have an Chiral molecule,but still i am not know in this list who have it. thanks for help.

Homework Statement is this compound chiral??why or why not?? http://img827.imageshack.us/i/gmp.png/ Homework Equations The Attempt at a Solution i don't think it is...what do u think??

Homework Statement A sample of synthetic camphor contains both the d and l isomers in unequal amounts . The specific rotation of the sample is found to be -13.9 degrees . What is the enantiomeric excess of the sample? (A) 0.215 (B) 0.314 (C) 0.417 (D) 0.167 pleasez xplain ur...

I am a senior in high school and currently deciding on what I want to do with the rest of my life as many others are. I have always enjoyed optics. I enjoy reading up on optical physics and up and coming optical technology (and of course playing with lasers). My question is would I enjoy optical...

I constructing 3D shape of about 2 millimeters sized. Which kind of optical coating will give me 10 degrees of half view angle for reflected light in visual spectrum ? thanks Alex

When we drive a car on a hot day we have all experienced what appears to be water on the road. I believe that this is related to the facts that 1) the air near the hot pavement is less dense than the air a few feet above and 2) light will travel from point A to B along the fastest path (in this...

Homework Statement The sugar concentration in a solution (e.g., in a urine specimen) can be measured conveniently by using the optical activity of sugar and other asymmetric molecules. In general, an optically active molecule, like sugar, will rotate the plane of polarization through an angle...

How to specify a lens to increase angular responsivity of optical sensor? Sensor I presently use has angular responsivity +/-60 degrees at 50% level and I would like to increase it to +/- 80 degrees at 50% level or more. Which lens should I use? Please advice on design guidance for this...

Does anyone know where I can find free information on Spontaneous Emission? I can't seem to find even a basic lecture on the Rabi frequency. Please help me out! Thanks

Homework Statement In a Young's double slit-type experiment using light of 600 nm with 0.5 mm between fringes, a thin plate of glass (d = 100 micrometers, n =1.5) is placed over one of the slits. What is the lateral fringe displacement on the screen? 2. The attempt at a solution To be...

Hi, I am a physics undergrad designing a solar spectrometer as part of a senior design type course. If we have light incident from the sun onto some sort of telescope objective (say a single lens for simplicity, focal length "f" and aperture radius "R") and then a pinhole at the focal point...

Question: An optical fibre is 1.0 metre long and has a diameter of 20micro-meter. Its ends are perpendicular to its axis. Its index of refraction is 1.30. What is the maximum number of reflections a light ray entering one end will make before it emerges from the other end? A) 18000 B)...

I have a question concerning optical tweezers. How do you make sure that the focal plane of the beam and the laser are the same..? In other words, I can see the laser on my CCD image when it is reflected off the cover slide, but if I see the reflection of the laser then the beads that are...

I'm a senior in high school who is still trying to figure out what I'm going to do with the next few years of my life. Early on, I was planning on going for the all to frequently debated PhD in physics until I realized I would like to keep my sanity not to mention get a job. I just recently...

Hey all I am using optical fibers as a read-out medium form a PCB. I see interference in the data through this fiber. Can someone shed a light on the interference patterns on the optical fiber? Usually one should not see any electronic noise in fibers. How true is it and how to get around it...

These are some fun illusions. http://videogames.yahoo.com/events/brain-teasers/brain-teasers-and-optical-illusions/1400154

A couple of days ago I burnished a very rusty old piece of steel with a fine steel wool. It's now very smooth, and there is no loose rust scale. It has a finish somewhat like a century-old doorknob in some old building at a university. Some place where hands have rubbed it many thousands of...

Is there an experiment that uses photons or other particles to measure the effect of Earth's rotation on them? Thanks

I've searched the net and haven't found an explanation for the term, so hopefully this will now return on searches for people. Besides, I'm confused about the term myself. What is meant by "optical conductivity"? How is it different from say a DC conductivity in J = cE where c is...

Homework Statement You see an optical illusion of an ever-upward spiral staircase. The climber trudges up and up and never gets anywhere, going in circles instead. Suppose the staircase is provided with a narrow ramp, allowing the tired stair-climber to push a wheelbarrow up the stairs. The...

Are there any applications of optical devices in environmental science? What technologies, companies and research groups are involved?

I studied optical tweezer, So I saw the optical path in the diagram. Then I can't understand why they use the Wollaston Prism? After launch the laser, the beam through the half-wave plate So the beam polarized, I know this. and after through the half-wave plate, the beam through...

How can we derive or prove the principle of optical reversibility from more basic principles?

Can someone give an intuitive explanation for this effect? I didn't go through the derivation carefully, but I know that the upshot of the math is that the dipole feels a force in the direction of the intensity gradient, so it goes to the focus of the laser. But I feel like there must be some...

I. Overview Another SA asked me to elaborate on a remark I made to the effect that frequency shift phenomena always (even in Minkowski vacuum) involve at least the following ingredients: two (proper time parameterized) timelike curves C, C' an event A on C ("emission event") an...

Dispersion Relation: w2=B(1/m+1/M)+-SQRT[(1/m+1/M)2-(4sin2ka/mM)] For waves on a diatomic row of masses, what is the physical meaning of acoustic and optical branches of this dispersion relation? What is the expression for the maximum frequency of the optical branch? Really stuck on...

Hello all, what is meant by soft optical modes. Is it just the Einstein modes with low frequency ? thanks.

Hi, I have been assigned to a new task in my job where I have to investigate on measuring the distance to an object by means of optical interferometry (Michelson interferometry). I have been looking for info on the subject but have not been really lucky. I have been able to obtain the...

Anybody else had this? It's a recognised medical phenomenon that's quite bizarre, slightly unsettling and could lead the gullible into all sorts of hysterical beliefs. In my lifetime so far it's happened just twice. And that's a long, long time. You get a little spot of scintillation...