Loading [MathJax]/jax/output/CommonHTML/jax.js

Sunday, August 16, 2015

Still Looking For Brewster

From the post "Late Bloomer Gets The Splits" dated 10 Aug 2015,

B1sin(αadj1)=B2sin(αadj2)

B1μ1cos(αadj1)=B2μ2cos(αadj2)

αadj1=90o+α1θ1

αadj2=90o+α2θ2

but when,

α1=θ1

cos(αadj1)=cos(90o)=0

or when,

α2=θ2

cos(αadj2)=cos(90o)=0

in which case,

μ1tan(αadj1)=μ2tan(αadj2)

is not valid,

The tangential component of the incident ray is zero and the ray enters the medium perpendicular to the inter-surface, parallel to the normal.  α2s passes through the second medium perpendicularly.

In a similar way, when we consider the left arm,

B1sin(αadj1)=B2sin(αadj2)

B1μ1cos(αadj1)=B2μ2cos(αadj2)

αadj1=θ1+α190o

in the first medium, and into the second medium,

αadj2=θ2+α290o

If θ1+α1=90o

sin(αadj1)=sin(0o)=0

or when,

θ2+α2=90o

sin(αadj2)=sin(0o)=0

the perpendicular component of the left incident arm is zero.  The tangential component  α2p, glides along the surface (if it is flat) and does not enter the second medium.

Both scenario occurs when,

θ1=α1

and

θ2+α2=90o

The incident ray is split 90o one along the surface α2p, and the other enters the second medium perpendicularly α2s.  This is wrong, velocity along the ray was not accounted for.


This is still not Brewster angle.  But, from

θ2+α2=90o

θ2=90oα2

θ1=α1

Since, from the post "A Bloom Crosses Over" dated 10 Aug 2015,

tan(θ1)tan(θ2)=ε2ε1

tan(α1)tan(90oα2)=ε2ε1

tan(α1)tan(α2)=ε2ε1

From Snell's Law,

n1sin(α1)=n2sin(α2)

n1n2sin2(α1)cos(α1)cos(α2)=ε2ε1

and

sin2(α1)cos(α1)cos(α2)=ε2ε1n2n1

α1+α2=90o  This is wrong!

sin2(α1)cos(α1)cos(90oα1)=ε2ε1n2n1

sin(α1)cos(α1)=tan(α1)=ε2ε1n2n1

which is still not Brewster.