Basic Optics

1
Basic Optics
2
Introduction

• Geometric Optics- rays
• Physical Optics - wave nature
• Quantum Optics - interaction of light with matter
• Refractive Index
• solids 1.5-2.5
• liquids 1.2-1.5
• gases 1

3
Geometric Optics

• Point Source, Spherical Waves
• Point source, field and intensity, wave and ray
• Interaction of Light with Surfaces
• Reflect, scatter, absorb, transmit on smooth
  surface
• Reflection on air-glass interface n1.5, R4
• Refraction and Reflection
• Refraction- differing velocities of rays in two
  media
• Snells Law

4

• Plane Surfaces
• Plane Mirrors
• Total Internal Reflection Prism over Mirrors
• Refraction of diverging rays
• Refraction by a prism
• Prism spectrometer variation of refractive
  index with wavelength
• Dispersion, angular and linear dispersion
• Refraction at a spherical interfaces lens and
  mirror
• Sign Convention
• Gaussian Formula
• Thin Lens and Spherical Mirror
• Ray Tracing Principles
• Parallel to focal point
• Through the focal point to parallel

5

• Lens Makers Formula
• Focal length refractive index and radius of
  curvature
• Lens Power 1/f (diopters when f in meter)
• Lens Combination
• Telephoto lens
• Eyepiece
• Spherical Mirror
• Spherical aberration Parabolic, Elliptic Mirror

6

• Aperture and Field Stops
• Controls Image aberration and depth of focus
• But not the angular field of view
• Relative aperture, speed of lens Ff/d
• Aberration
• Spherical
• Defects of imaging properties of spherical
  surfaces
• Can be cured with cemented doublet
• Coma, Astigmatism, Field Curvature and distortion
• Coma aplanatic
• Astigmatism Difference of Plane I and Plane II
• Higher order Field Curvature, Field Distortion
• Chromatic Aberration
• Cure Achromatic Doublet

7
Physical Optics

• Wave, and Waves
• Dielectric Interface
• Interference of Two, and Multiple Beams
• Interference of cylindrical waves from two slits
• Constructive and destructive fringe easily
  visible when D/dgtgt1
• Fabry-Perot Interferometer
• Layers of Film
• Filters and Coatings

8
Diffraction

• Diffraction by a slit
• Single slit A set of lines
• Resolving Power of a rectangular aperture
• Fraunhofer - Circular Aperture
• Diffraction Grating
• Diffraction Patterns for M1, 2, 3,,,
• Order of diffraction
• Grating Transmission and Reflection Gratings
• Blaze angle
• Grating Spectrometers
• Ebert,
• Czerny-Turner

9
Lasers and Applications

• Principles
• Light Amplification by Stimulated Emission of
  Radiation
• MASER
• LIDAR
• Radiative Transitions
• Spontaneous
• Absorption
• Stimulated Emission
• Line Broadening Not perfectly monochromatic
• Lorentzian
• homogeneous broadening, finite lifetime of the
  energy levels for spontaneous emission and
  interaction of emitting molecules with latice
  vibration
• Gaussian
• Doppler-shift of frequency due to random thermal
  motion
• Absorption, Amplification, Population Inversion
• Laser Oscillators
• Axial modes
• Higjer Order Transverse Modes
• Polarization

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Common Laser Types

• Ruby
• Nd YAG
• 1.064 um, (pulsed version to generate second
  (visible) and third(uv) harmonic,
• He-Ne,
• 0.6328 um(red)
• Typical 10 milli watts
• Ar
• 0.488 um(blue), 0.5145 um(green)
• Cw output of 1-10 watts
• LDV, to pump a dye laser, low efficiency (0.1)
  1-10 kW with water cool
• CO2
• Molecular vibrational rotational transition
• 10.6 and 9.6 um, order of 10 watts ,
• Semiconductor,
• Organic Dye Lasers, ,

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Some Features

• Laser Brightness
• Even low intensity lasers emit relatively high
  intensity light (per area per solid angle per
  wavelength band)
• Linewidth and Temporal Coherence
• Wavelength coherence 1E-17
• Amplitude fluctuation
• Loosely defined coherence time 1E-7 sec
• Coherence length few cm for multi mode Argon
  Ion
• Gaussian Beams

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Gaussian Beams

• Gaussian Spherical Wave vs. Uniform Spherical
  Wave
• Gaussain Beams
• Radially exponential-gt beam radius
• Axially spherically diverging -gt beam waist
• Typical values
• Waist 0.5 mm
• Wavelength 0.5 um
• Waist location 1.6 m (common bench is in the
  near field)
• Half angle of divergence 3E4 radians, 0.02 deg
• Beam expanding telescope

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Lab - Basic Optics

• Lens and Mirror
• Lens Law - Positive and Negative, Lens and
  Mirror
• Focal Length, Image (Real, Virtual)
• Bellows
• Lasers
• Beam Waist, Beam Expander
• Polarization
• Slit and Pinhole - Diffraction Pattern

14
???? ??

• Newport
• Edmund Optics
• Coherent
• Hamamatsu
• Melles Griot
• Sigma
• Photonics
• Spectra Physics(http//www.spectra-physics.com/Int
  ercept/SP404.htm)
• Oriel
• ????
• www.kosinc.co.kr
• www.optron.co.kr