Parviz Parvin

12 Questions 162 Answers 0 Followers

Questions related from Parviz Parvin

In all optical autocorrelation for femto-second pulse measurement: Why is a nonlinear SHG crystal situated in front of the detector?

There are two major techniques to measure ps - fs pulses of the mode-locked lasers: I) Steak camera II) Optical autocorrelation According to the space-time transformation in second-order...

02 January 2016 7,466 3 View

What are the advantages and disadvantages of Stable versus unstable resonator?

Laser with stable resonator creates the axial and traverse modes. The mode frequency is a function of mirror radii and the resonator length as well as the effect of transverse modes. What about...

06 March 2015 9,116 4 View

What are the differences between ASE and laser?

Amplified spontaneous emission (ASE) is so strong in high gain lasers (dye, excimer, FEL, etc.) that may be mistaken with the coherent light. How can we distinguish and suppress ASE?

06 March 2015 6,031 15 View

What are the techniques to measure the temporal and spatial coherence of a laser beam?

I know Michelson Interferometry for the temporal and coherence length measurements and Shack-Hartmann wave front sensor for the spatial coherence detection. What else do you suggest?

17 February 2015 5,558 9 View

Is there any relation between coherence and polarization as two distinct properties of light?

To my knowledge, there is no solid correlation between temporal or spatial coherence and the polarization of light (linear, circular or elliptical) because the coherence arises from the nature of...

05 January 2015 3,998 12 View

What is the best model to predict multiple scattering in highly scattering media?

There are a number of models to analyze propagation of light in scattering media, including ballistic, diffusion, Kublai-munk, Monte-Carlo etc. The multiple scattering resembles to be dominant in...

05 January 2015 7,914 3 View

What happens for a depolarization lidar to transmit circular polararized instead of linearly polarized coherent light ?

The de-polariztion lidar functions based on linear polarization of laser. An electro -optical Q-Sw Nd:YAG laser is usually used. The depolarization ratio is measured by the detection of...

17 September 2014 3,011 9 View

Does the focal point of an ideal lens vary with different phase fronts from the incident beam?

The planar phase front and the spherical phase front may change the focal point of an ideal micro-lens ( having min aberration). This fact may be enhanced drastically for an incident distorted...

18 February 2014 650 46 View

Why is the electron mobility of graphene extraordinarily high?

Graphene is a nano structure. It is a 2-D carbon sheet with a honeycomb structure that exhibits extraordinary physical and electrical properties. One outstanding electrical property of graphene is...

16 December 2013 4,967 5 View

The human eye is similar to other light detectors. Its function is based on photon property and not its wave characteristics.

Does it mean that light is particle? To my knowledge , the light detectors within any spectral range detects light based on photon property of light. The array detector function is also based on...

28 November 2013 2,255 33 View

Is there any attempt to model "Physics of Cancer"?

Cancer consists of a series of diseases based on undesired cell proliferation. The cancerous cells are continuously formed in infectious organs whereas the human immunity system regularly...

16 November 2013 2,253 82 View

How can we find any correlation between stimulated emission and coherence to rewrite the rate equations?

Despite the set of rate equations formulate the instantaneous population of the upper and lower levels, the population inversion of laser transition, gain and saturation properties, however those...

09 November 2013 4,378 6 View