LASERS

Question 1

Brewster’s angle

Answer 1

Theta B=tan^-1 (n2/n1)

Question 2

homogenous broadening

Answer 2

effexts all atoms in the same way, each atom will therefore display the same line profile as all other atoms.

Question 3

examples of homogenous broadening

Answer 3

natural lifetime and pressure broadening

Question 4

inhomogenous broadening

Answer 4

affects all atoms in different local environments in a different way producing differnt line profiles

Question 5

inhomogenous boradening

Answer 5

doppler

Question 6

Beam of radiation through a medium

Answer 6

vr=E2-E2/hbar

Question 7

rate of decay spontaneous emission

Answer 7

(dN2/dt)sp = -A21 N2

Question 8

Rate of population (abs)

Answer 8

(dN2)/dt)abs=B12p(v)N1

Question 9

P(v)

Answer 9

is the energy density of photons of frequnecy v

Question 10

B12

Answer 10

eistenins coefficient for absorption

Question 11

A21

Answer 11

eisteins coefficient for emission

Question 12

rate of decay of stimulated emission

Answer 12

(dN2/dt)sti = -B21p(v)N2

Question 13

N1 KT relation

Answer 13

N1 proportional exp(-E1/KT

-(E2-E1)/KT = -hv/kT

Question 14

thermal equilibrium is reached when

Answer 14

N1B2P(V) = N2A21 + N2B21P(V)

Question 15

Threshold for lasing equaiton

Answer 15

fout/fo = R1R2exp(2alphanL)1

Question 16

laser cavity equation

Answer 16

nlambdan/2=l

Question 17

longitudinal modes

Answer 17

determines the emission spectrum of the laser

Question 18

Transverse modes

Answer 18

describes the intensity variation within a cross-sectional slice of the laser beam. THe modes are labelled TEMmn where m and n are integer numbers of transverse mode lines in the x and y directions across the emerging beam