Ask Question, Ask an Expert


Ask Electrical & Electronics Expert


Wave Retarders in Tandem

prepare the Jones matrices for the following retarders:

(a) A π/2 wave retarder with the fast axis along the x direction.

(b) A π wave retarder with the fast axis at 45° to the x direction.

(c) A π/2 wave retarder with the fast axis along the y direction.

If these three retarders are placed in tandem, with (c) following (b) following (a), find the resulting rotation. What happens if the order of the three retarders is reversed?


Maximum Extraordinary Effect

Determine the direction of propagation in quartz (ne = 1.553 and no = 1.544) at which the angle between the wave vector k and the Poynting vector S (which is also the direction of ray propagation) is maximum.


Double Refraction

An unpolarized plane wave is incident from free space onto a quartz crystal (ne = 1.553 and no = 1.544) at an angle of incidence 30°. The optic axis lies in the plane of incidence and is perpendicular to the direction of the incident wave before it enters the crystal. Determine the directions of the wave vectors and the rays of the two refracted components.


Transmission Through a LiNb0 3 Plate

Examine the transmission of an unpolarized He-Ne laser beam (λo= 633 nm) normally incident on a LiNb0 3 plate (ne = 2.29, no = 2.20) of thickness 1 cm, cut such that its optic axis makes an angle 45° with the normal to the plate.

a) Find out the lateral shift at the output of the plate and the retardation between the ordinary and extraordinary beams.

b) Sketch the beams


Field Distribution

The transverse distribution um(y) of the electric-field complex amplitude of a TE mode in a slab waveguide is given by:

1384_Transverse distribution.jpg

Derive an expression for the ratio of the proportionality constants. Plot the distribution of the m = 0 TE mode for a slab waveguide with parameters n1 = 1.48, n2 = 1.46, d = 0.5 μm, and λo == 0.85 μm, and determine its confinement factor (percentage of power in the slab).

Coupling Coefficient between Two Slabs

683_Coefficient between slabs.jpg

a) Find out the coupling coefficient between two identical slab waveguides of width d = 0.5 μm, spacing 2a = 1.0 μm, refractive indexes n1 = n2 = 1.48, in a medium of refractive index n = 1.46, at  λo = 0.85 μm. Assume that both waveguides are operating in the m = 0 TE mode and use the results of Ques. 5 to determine the transverse distributions.

(b) Determine the length of the waveguides so that the device acts as a 3-dB coupler.


Modal Dispersion in Step-Index Fibers

Find out the core radius of a multi-mode step index fiber with a numerical aperture NA = 0.1 if the number of modes M = 5000 when the wavelength is 870nm. If the core refractive index n1 = 1.445, the group index N1 = 1.456, and Δ is approximately independent of wavelength, determine the modal-dispersion response time σT for a 2-km-Iong fiber.


Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a type of spectroscopy that uses plasma generated by a laser pulse. A schematic of a LIBS system is shown in the figure below. The laser is focused on the sample and forms plasma, which atomizes and excites samples. LIBS has the capabilities of analyzing any material regardless of its composition (solid, liquid or gas). When a material breaks down and forms plasma of sufficient temperature, it emits light at characteristic frequencies (spectrum) that corresponds to the material. LIBS can (in principle) detect all elements, limited only by the power of the laser and the spectral sensitivity of the spectrometer & detector. The detection limit of the LIBS spectrometer is a function of a) the plasma temperature b) spectral pass band of the optical system, and c) the strength of the spectral emission being viewed.


The LIBS system presented in Figure 1operates by focusing the laser onto a small part of the sample with sufficient power to ablate a very small amount of material.

Typically only a few nanograms of material ablated from the sample. This ablated material generates a plasma plume with temperatures in excess of 100,000 K. This plasma quickly cools to a temperature in the range of 5,000–20,000 K. At these temperatures the plasma plume is imaged. When the plasma is first formed it emits a continuum of light (i.e. white light) When the plasma cools and expands the spectral lines of the elements present in the plasma start to be observable. The delay between viewing the emission of continuum radiation and the spectral signature of the materials present is approximately 10μs from the laser  pulse.


Part 1 System Understanding

Referring to above Figure describe the purpose of the following subsystems, identifying each component in the path.

Transmission path:
Receiver Path:

Transmission Path

The laser source is a 1064nm Nd:YAG laser with a pulse width of 10ns. The average output power of the laser is 750W. The waist location is at the output window of the laser and has a diameter of 1mm. Assuming that it takes an intensity of 3.4 GW/cm2 to ablate the surface of the material of interest, what is the diameter of the beam on the sample? What F# is necessary to achieve this spot size? If the focal length of the lens is 100mm what is the Diameter of the lens (f3)? If the output of the laser has a diameter of 1mm and is a waist of the laser, determine the distances z1 and z2. Determine the distance z3. find out the radius of the beam assuming a Gaussian profile. Assuming it takes more than 75% of the peak intensity to form plasma, determine the tolerance on the sample location. (How accurate do you need to place the sample to get a signal?)

Receiver Path

One of the advantages of LIBS is that spectrometer which is used to analyze the plasma spectrum can be separated from the event by a distance with the use of a fiber optic cable. Assume for this design that the fiber optic cable is an 8/125 cable made of fused silica. For the purpose of this problem take the index of refraction of the core to be 1.46 and the cladding to be 1.42. What is the NA, the acceptance angle, θc, and ¯θc of the fiber? How many modes propagate down the fiber? Using this information, what is the focal length of the lens used to focus the light from the plasma into the fiber? At the other end of the fiber is a grating, lens, and linear CCD array. Sketch the configuration of this system used to collect the light diffracted by the diffraction grating onto the CCD Array. The grating has a Λ= 2000nm. What is the range of angles diffracted for a wavelength range from 400nm to 1000nm? Supposing that each pixel of the CCD array is 5 microns and that there are 4096 pixels in the linear array. What is the focal length of the lens? Find the wavelength resolution of the CCD Array?

Electrical & Electronics, Engineering

  • Category:- Electrical & Electronics
  • Reference No.:- M91758

Have any Question? 

Related Questions in Electrical & Electronics

1 what is the main difference between live audiovideo and

1. What is the main difference between live audio/video and real-time interactive audio/video? 2. When we use audio/video on demand, which of these three types of multimedia communication takes place: streaming stored au ...

1 what are the names of the protocols discussed in this

1. What are the names of the protocols, discussed in this chapter, that provide security for e-mail? 2. How does PGP create a set of security parameters? 3. What is the purpose of the Handshake Protocol in SSL? 4. What i ...

A determine the magnitude of the x and y components of the

(a) Determine the magnitude of the x and y components of the force exerted on the fixed blade shown by a 3-ft 3  /s jet of water flowing at 25 fps. (b) If the blade is moving to the right at 15 fps, find the magnitude an ...

A liquid of density rho flows through a sluice gate as

A liquid of density ρ flows through a sluice gate as shown. The upstream and downstream flows are uniform and parallel, so that the pressure variations at stations 1 and 2 may be considered hydrostatic. (a) Determine the ...

The state equations of a certain system are given asfind

The state equations of a certain system are given as Find the state equations of the system with w as the state vector. Determine the characteristic roots (eigenvalues) of the matrix A in the original and the transformed ...

1 why is it necessary to have the minus sign associated

1. Why is it necessary to have the minus sign associated with the time rate of increase of magnetic flux on the right side of Faraday's law? 2. What is electromotive force? 3. What are the different ways in which an emf ...

Consider a nonlinear elastic uniaxial bar element under tip

Consider a nonlinear elastic uniaxial bar element under tip force F = 100 N shown in Figure. The stress-strain relation is given in terms of Cauchy stress and engineering strain in the deformed geometry: σ11 = Eε 11 . Us ...

1 explain why private-public keys cannot be used in

1. Explain why private-public keys cannot be used in creating a MAC. 2. The nonce in Figure 31.22 is to prevent a replay of the third message. Eve cannot replay the third message and pretend that it is a new request from ...

1 state the relationship between polarization current

1. State the relationship between polarization current density and electric field intensity. How is it taken into account in Maxwell's equations? 2. What is the revised definition of D? 3. State the relationship between ...

1 what is the significance of a nonzero net right-lateral

1. What is the significance of a nonzero net right-lateral differential of and normal to the z-direction at a point in space? 2. If a pair of E and B at a point satisfies Faraday's law in differential form, does it neces ...

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

WalMart Identification of theory and critical discussion

Drawing on the prescribed text and/or relevant academic literature, produce a paper which discusses the nature of group

Section onea in an atwood machine suppose two objects of

SECTION ONE (a) In an Atwood Machine, suppose two objects of unequal mass are hung vertically over a frictionless

Part 1you work in hr for a company that operates a factory

Part 1: You work in HR for a company that operates a factory manufacturing fiberglass. There are several hundred empl

Details on advanced accounting paperthis paper is intended

DETAILS ON ADVANCED ACCOUNTING PAPER This paper is intended for students to apply the theoretical knowledge around ac

Create a provider database and related reports and queries

Create a provider database and related reports and queries to capture contact information for potential PC component pro