Optical Definition and 640 Threads

Hi everyone How can I determine the optical band gap of a cobalt ferrite film deposited on a glass substrate using its absorption, transmittance and diffuse reflectance spectrum (knowing that I don't know the thickness of this film)

I work in a lab that uses laser probes to test for vibration and other data, currently the lab techs hook up the probe to a laser source and check to see how bright and clear the beam spot is. I have been working on having a signal power budget created for each probe using a laser source and...

What is the physical meaning of acoustic and optical branches in phonons dispersion curves ?

Hi. I know how optical fibers work but where is the information in the light signal passing through it? Which characteristics of the electric field carry it? I begun to think about it because I was intrigued if they took into account things like the Goos-Hänchen shift or angular deviations in...

First of all i will post a picture of it ... you can find it ... somewhere sorry this is my first post :I I photographed our television with the flash on in order to recreate a strange patter i saw when looking at the suns reflection in the screen.(with my eyes it's not just the camera) You can...

Hello friends. My question consists two parts, 1-What is the difference between an optical and an acoustic phonon? 1-What are the conditions by which we can decide the type of phonon i.e optical or acoustic phonon ? Hope to get the reply soon.

How does the claddibg with lower refractive index reduce the light loss from the core? Thank you.

I am currently working on project for trapping RBC's using optical tweezers but i think i am making a mistake in preparing the sample. Can anyone provide an appropriate sample preparing method ?

I understand that otical bistability only occurs in a specific parameter regime defined by the bimodial leaf, but I have read that bistability originates from highly non linear dynamics of the system. As we are dealing with a qubit in a cavity that is being driven so things become non-trivial...

What are the different formulas for the calculation of magnifying power of a microscope and a telescope? And how would we use the sign conventions in them?

My questions is about the conversion of a range of wavelengths in Hz, such as for an optical filter, in a medium different from air. Since the refractive index n is higher than 1, (let's say n=1.5) and than the value of c is almost 2x108 m/s, also the equation in the link below has to be...

What kind of frame of reference do I have to choose when I'm studiyng lens and mirrors? As far as I know you consider positive the direction where the rays are real and negative the one where the rays are virtual, is that always true? Why can't we study a problem of optics choosing a frame of...

Hello, I'm currently a Senior year EE student in a South Asian country. We are planning to do a research project on Optical Nanoantennas. We are still learning and are not very familiar with the theoretical stuff, we only have the knowledge of junior year undergrads (took EM Fields and Wave...

Hi there, optical aberrations can be expressed by Zernike polynomials Vmn(ρ,θ). Now, for my simulations i am using software that takes 4 inputs for creating aberrations onto an optical flat: m,n,R,A m,n are the Zernike orders which is perfectly clear. For R,A the manual says: R: the radius A...

This post is related to a posting I did a couple of days ago, but I will go into more detail on this one, and it should be more easy to see the concept that is presented. A number of years ago, I was explaining interference concepts to a physics Ph.D. who had very little background in...

Hello! In this previous post, most replies point out that it is not possible to predict the angle of refraction (and so the frequency) at a certain interface, given the wavelength of the original signal. In particular, But when dealing with optical waveguides, it seems to be different. I am...

I am interested to use a pyrometer to measure the temperature of a graphite heater while it is being heated (upto 1200 degC). The heater is located inside a small chamber filled with liquid cyclohexane . For viewing purpose of the pyrometer the chamber is having a viewport of Quartz. The...

We use lasers containing various elements in vacuums on Earth all the time. Is it possible to use lasers in the dirty vacuum of space to take pics and transmit at near the speed of light?

Hi, i was doing a science project on LEDs, and i needed to calculate optical output power versus input electrical power to find relative wall plug efficiency. This is the only good formula i found Optical output power of LED (watts) =Nlinearfactor × Voltage drop across resistor (volts) Pout = N...

I want to know the relationship between the optical axis direction of a crystal and the dielectric constants in different directions in an anisotropic material.

Hello, again a simple question: consider a mirror, with a transparent layer (index of refraction n) of certain thickness on it. If a ray is reflected by the mirror, while the mirror is moved normal to the plane, then one could observe a dopplershift. But what happens if the mirror is fixed...

Hello, I have a simple question. Suppose a perfect point source in front of a mirror. The virtual image of the point source acts like a second point source. Now let's look at the interference of the direct point source light and the virtual point source, at some position. Since the path...

Hi everyone. I'm looking for some help from someone expert in optics to create an inteferometry based setup to map the surface of a small object. This is for a small lab project so I'm not looking for a really complex setup, I just need something simple that can be built in a short amount of...

Hello everyone. I have been practicing for my exam in fiber optics, and stumbled upon the following question: We have a transmission system with 3 channels, composed of a single mode fiber and a dispersion compensation fiber. Specifications are given for each. We need to calculate the channel's...

Hi, I have read from previous topic regarding color of light vs wavelength. It is a bit confusing for on my self as I do not have any background on this. Hopefully someone could chime in and educate myself. Here it goes, it has been lingering in my head that the color of light emitted by a...

How one can analyse an image of a solid material obtained with an optical microscope ?

Hi there, Is it easily possible to change to optical engineering for the MSc and being involved in big telescope constructions after getting a BSc degree in mechanical engineering? Lucius

I am working on a thesis, but new to programming. What is the best and easy to use program that I can use for the work: Measurement and analysis of elastic scattering of alpha–particle and light heavy ion scattering using nucleon-nucleon interaction

I'm preparing a poster presentation on the following paper for a physics course: http://t.co/xiCLV7Y0ZH I do not understand how figure 4 tells us about the red/blue shift. Just from the deflections of the peaks of the airy beam, as well as the deformation, how are we able to infer that there is...

Homework Statement The complex amplitudes of a monochromatic wave of wavelength ##\lambda## in the z=0 and z=d planes are f(x,y) and g(x,y), redprctively. Assume ##d=10^4 \lambda##, use harmonic analysis to determine g(x,y) in the following cases: (a) f(x,y)=1 ... (d) ##f(x,y)=cos^2(\pi y / 2...

Do you guys know a low-cost low-threshold optical beam limiter, with cost somewhere ~$100. Or if you know certain method to fabricate such. I would be greatful if you could include links and/or references. I am still noob in photonics so I am only familiar with a beam limiter that blocks the...

I was reading about a process called up-conversion mentioned in Robert Boyd's Non-Linear Optics. It is essentially a special case of sum frequency generation (in sum frequency generation, two waves of different frequencies are sent into the crystal, and out comes a wave with a frequency equal to...

Is there anyone who has experience in setting up optical system for exciting a sample using Q-switch mode of Nd:YAG laser? I am currently looking at the optical system which I did not setup (someone else did, but the person is absent and cannot contact). I have no background whatsoever in...

Hello, I am looking into building a touch screen. I have been considering a capacitive touch screen but I am also interested in optical touchscreen using infrared like the ones one this link...

During optical pumping in a laser, is the wavelength of light that corresponds to the transition from the metastable state that yields the laser light removed? Otherwise, wouldn't a population inversion not be possible as these photons from the optical pumping would cause stimulated emission...

There are very results published about PT symmetry breaking in optical systems, with effects like anysotropical transmission resonance in waveguides. But if PT symmetry is broken in a optical system and CPT symmetry must always be respected, then what C symmetry is broken in a optical system?

I can't understand how eye actually works. From what I understand when I look at 2 objects of the same size The object that is further is smaller in the final image because light rays reflected from it take smaller surface at the retina (Here B is smaller than A because rays take less surface at...

I have a few questions regarding an optical microscope and their white light sources... So white light generally first hits a diffuser, some kind of ground glass lens. What is the purpose of this? Then the light goes through a field diaphragm, which we can open and close. I have heard that...

In a measurement of an OSL spectrum the wavelength of the stimulation source is always higher than the wavelength of the emission of the material. Is this due to the fact that at lower wavelengths one can no longer distinguish between stimulation and emission light? Can electron traps be...

I am entering my final year as a physics/math double major undergrad and have hopes to continue onto a PhD program where I can do optics research, either through a physics or ECE department. That being said, my interests lie in experimental work rather than computational or theoretical, but I...

Greetings I am not a physicist myself, so please forgive me, if my question/proposition will sound naif. I noticed some articles about accelerating electrons using laser and glass gratings: http://phys.org/news/2013-09-chip.html http://phys.org/news/2013-10-particles-compact-particle.html I...

Can anyone explain why a photon seems to travel in a perfectly straight 3D line over unimaginable distances? What exactly defines a straight-line? The concept appeals to Cartesian coordinate space. Is there any way to quantify the straightness of a photon path? Or, does the path taken by...

Hello Forum, The aperture stop (AS) of an optical system is that physical aperture in the system that limits the amount of light from the object. Consider a 2D object formed by point objects. The AS is determined by considering the object point that is located on the optical axis. Will the AS...

I have done basic experiments where a laser is shot thru a grating and a lens is inserted at the diffraction pattern to put the spectra back together and form an image of the grating. apart from this being the single most mind blowing experiment ever to witness I have some questions about the...

Hi everyone! This is my first post. I hope I am posting in the right place -- if not, please let me know. I am also hoping my question will not sound too absurd; I am no physicist, just someone who would like to use complex technology to create an art installation, and I'm having a hard time...

Aluminium has an fcc structure, which is a simple cubic lattice with four Al-atoms in the basis. On the other hand, diamond has a diamond structure, which is a simple cubic lattice with 8 atoms in basis. Now, diamond has optical modes in addition to acoustical, while Aluminium does not. What...

I'm a novice studying laser physics and I came a across the condition for optical gain: \frac{N_2}{g_2} > \frac{N_1}{g_1} This is a basic set up where N_1 is the number of atoms in the lower energy state and N_2 is the number of atoms in the higher energy state. g_1, and g_2 are the...

I am going over the optical theorem (specifically from Sakurai) and I just have a simple couple of questions. The optical theorem says \sigma_{total}=\frac{4\pi}{k}\text{Im}(f(0)) Where ##f(0)## is the scattering amplitude in the forward direction. (Which I am assuming means the direction...

Hey! I've a simple (and maybe stupid) question about the accuracy of an OSA. The datasheet report a level accuracy of 0.4 dB but this seems quite strange to me. Indeed level measurements are done in dBm thus, as long as dB measures a relative power, I assume that even the 0.4 dB are referred to...

Homework Statement A thin film of dielectric material of refractive index 1.455 and thickness 6.50 mm is now placed over one of the slits (say the right-hand one). By how much will this change the optical path between the slit and the centre of the screen? Homework Equations Optical Path...