10: Lasers

Example number 1, Page number 10-20

In [2]:
#importing modules
import math
from __future__ import division

#Variable declaration
c=3*10**8;                 #velocity of light(m/s)
h=6.63*10**-34;            #plank's constant(Js)
e=1.6*10**-19;             #charge(coulomb)
lamda=1.55*10**-6;         #wavelength(m)

#Calculation
Eg=h*c/(lamda*e);          #band gap(eV)   

#Result
print "band gap is",round(Eg,1),"eV"

band gap is 0.8 eV

Example number 2, Page number 10-20

In [5]:
#importing modules
import math
from __future__ import division

#Variable declaration
c=3*10**8;                 #velocity of light(m/s)
h=6.63*10**-34;            #plank's constant(Js)
e=1.6*10**-19;             #charge(coulomb)
Eg=1.44*e;                 #band gap(eV)   

#Calculation
lamda=h*c*10**10/Eg;       #wavelength(angstrom)

#Result
print "wavelength is",int(round(lamda)),"angstrom"

wavelength is 8633 angstrom