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Page 1: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

If  

then  

The composite ray matrix for an imaging system

AND  

Page 2: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

If  

then  

The composite ray matrix for an imaging system

AND  

THUS  

Page 3: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is
Page 4: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is
Page 5: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that maps a point emitter in the object plane at d1 to a point in the image plane at d2

Page 6: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

Page 7: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

What is the sign of R?

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

Page 8: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

What is the sign of R?

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

Recall for a Gaussian Beam

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 9: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

What is the sign of R?

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

Recall for a Gaussian Beam

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 10: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

What is the sign of R?

Convention: curvature positive if source to the left

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

Recall for a Gaussian Beam

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 11: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

2i)  The  image  equaLon  implies  that  a  spherical  wave  with  a  parLcular  origin  and  radius  of  curvature  hiQng  the  lens  is  transformed  to  a  new  spherical  wave  with  a  different  radius  of  curvature  and  origin.    Write  down  the  transformaLon  law  for  the  radii  of  curvature.    BEWARE  THE  SIGN  OF  R  !  

Page 12: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

2i)  The  image  equaLon  implies  that  a  spherical  wave  with  a  parLcular  origin  and  radius  of  curvature  hiQng  the  lens  is  transformed  to  a  new  spherical  wave  with  a  different  radius  of  curvature  and  origin.    Write  down  the  transformaLon  law  for  the  radii  of  curvature.    BEWARE  THE  SIGN  OF  R  !  

2j)  Given  q’s  relaLon  to  R  derive  the  transformaLon  law  for  a  Gaussian  beam  q-­‐parameter  

Page 13: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

2i)  The  image  equaLon  implies  that  a  spherical  wave  with  a  parLcular  origin  and  radius  of  curvature  hiQng  the  lens  is  transformed  to  a  new  spherical  wave  with  a  different  radius  of  curvature  and  origin.    Write  down  the  transformaLon  law  for  the  radii  of  curvature.    BEWARE  THE  SIGN  OF  R  !  

2j)  Given  q’s  relaLon  to  R  derive  the  transformaLon  law  for  a  Gaussian  beam  q-­‐parameter  

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

Page 14: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

2i)  The  image  equaLon  implies  that  a  spherical  wave  with  a  parLcular  origin  and  radius  of  curvature  hiQng  the  lens  is  transformed  to  a  new  spherical  wave  with  a  different  radius  of  curvature  and  origin.    Write  down  the  transformaLon  law  for  the  radii  of  curvature.    BEWARE  THE  SIGN  OF  R  !  

2j)  Given  q’s  relaLon  to  R  derive  the  transformaLon  law  for  a  Gaussian  beam  q-­‐parameter  

Page 15: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

Lens focal length: f

A lens is a device that maps a point emitter in the object plane at do to a point in the image plane at di

Image equation

2i)  Given  (2h)  what  can  you  say  this  system  does  to  transform  a  spherical  wave?  Draw  it!  Bonus)  What  does  this  system  do  to  a  the  q-­‐parameter  of  a  Gaussian  beam?  

2i)  The  image  equaLon  implies  that  a  spherical  wave  with  a  parLcular  origin  and  radius  of  curvature  hiQng  the  lens  is  transformed  to  a  new  spherical  wave  with  a  different  radius  of  curvature  and  origin.    Write  down  the  transformaLon  law  for  the  radii  of  curvature.    BEWARE  THE  SIGN  OF  R  !  

2j)  Given  q’s  relaLon  to  R  derive  the  transformaLon  law  for  a  Gaussian  beam  q-­‐parameter  

Page 16: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

A general optical system transforms q as

OR

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 17: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 18: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 19: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 20: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

recall

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 21: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

recall

the imaginary parts are equal !

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 22: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

the imaginary parts are equal !

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 23: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

the imaginary parts are equal !

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 24: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

the imaginary parts are equal !

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

BUT we need

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 25: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

the imaginary parts are equal !

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

BUT we need So divide all terms by f

lens

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 26: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

lens

recall

the imaginary parts are equal !

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 27: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

lens

recall

the imaginary parts are equal !

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

Page 28: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

A lens is a device that transforms a Gaussian q-parameter according to

3a)  Find  the  ABCD  values  for  the  lens.  

A general optical system transforms q as

OR

3b)  What  does  propagaLon  in  free  space  thru  a  distance  d  do  to  the  q-­‐parameter?  

3c)  Find  the  ABCD  values  for  free  space  propagaLon  thru  distance  d  

lens

distance

recall

the imaginary parts are equal !

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

Image  from  Fundamentals  of  Photonics  2nd  EdiLon  by  Bahaa  E.  A.  Saleh  &  Malvin  Carl  Teich  

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3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall

Page 30: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall

Page 31: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall BONUS  :  What  happens  as  z0  <<  f  ?  

Page 32: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall BONUS  :  What  happens  as  z0  <<  f  ?  

Page 33: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall BONUS  :  What  happens  as  z0  <<  f  ?  

Page 34: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall BONUS  :  What  happens  as  z0  <<  f  ?  

Page 35: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall BONUS  :  What  happens  as  z0  <<  f  ?  

Page 36: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall BONUS  :  What  happens  as  z0  <<  f  ?  

Page 37: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall

using  Ideal  minimum  spot  size  

What  happens  as  z0  <<  f  ?  

Page 38: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall What  happens  as  z0  <<  f  ?  

using  Ideal  minimum  spot  size  

Page 39: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall What  happens  as  z0  <<  f  ?  

using  Ideal  minimum  spot  size  

Page 40: The composite ray matrix for an imaging system · The composite ray matrix for an imaging system AND# If# then# The composite ray matrix for an imaging system AND# THUS# A lens is

The  input  beam  is  AT  ITS  FOCUS,  so  q  is  purely  imaginary  

3d)  Suppose  a  lens  is  placed  at  the  focus  of  a  Gaussian  beam.  Sketch  the  situaLon.  What  is  the  q-­‐parameter  before  and  aYer  the  lens?  Describe  where  and  what  is  the  minimum  width  of  the  beam  aYer  the  lens  in  the  limit  of  z0  >>  f.  

recall What  happens  as  z0  <<  f  ?  

The  lens  does  nothing…  

using  Ideal  minimum  spot  size