logo

johzu

About

Optics formulas


Remember that: a=a \vec{a} = \mathbf{a} , a˙=dadt\dot{a}= \frac{da}{dt} and Δa=afinalainitial=afai=a2a1\Delta a = a_{final} - a_{initial} = a_{f} - a_{i} = a_{2} - a_{1} . The \propto symbol is read as "is proportional to". While a^=aa\hat{a} = \frac{\vec{a}}{\Vert \vec{a} \Vert} is the unit vector.

Symbols

name symbol
amplitude AA
slit width aa
light velocity c=299 792 458 m/sc = 299\ 792\ 458\ \mathrm{m/s}
distance dd
energy EE
focal length, frequency ff
Planck constant h=6.626×1034 Js=4.136×1015 eVs\begin{split} h &= 6.626 \times 10^{-34}\ \mathrm{J \cdot s} \\ &= 4.136 \times 10^{-15}\ \mathrm{eV \cdot s} \end{split}
intensity II
distance from diffraction slits to screen LL
angular magnification (or amplification) MM
lateral magnification, diffraction number of order mm
near point approximation NPNP
refractive index nn
optical power PP
curvature radius (spherical mirror) rr
object distance ss
image distance ss^{\prime}
speed of light in a medium vv
object height yy
image height yy^{\prime}
phase difference δ\delta
wavelength λ\lambda
subtended angle θ\theta
phase difference of several waves ϕ\phi

Geometrical optics

name equation
refractive index n=cvn = \frac{c}{v}
reflection law θi=θr\theta_{i} = \theta_{r}
Snell's law of refraction n1sinθ1=n2sinθ2n_{1} \sin \theta_{1} = n_{2} \sin \theta_{2} sinθ1v1=sinθ2v2\frac{\sin \theta_{1}}{v_{1}} = \frac{\sin \theta_{2}}{v_{2}}
reflected intensity I=(n1n2n1+n2)2I0I = \left( \frac{n_{1} - n_{2}}{n_{1} + n_{2}} \right)^{2} I_{0}
total internal reflection critical angle sinθc=n2n1\sin \theta_{c} = \frac{n_{2}}{n_{1}}
Malus law I=I0cos2θI = I_{0} \cos^{2} \theta
Brewster angle, polarization angle tgθp=n2n1\tg \theta_{p} = \frac{n_{2}}{n_{1}}
Flat mirror.

Spherical mirror

name equation
mirror equation 1f=1s+1s\frac{1}{f} = \frac{1}{s} + \frac{1}{s^{\prime}}
focal length of a mirror f=12rf = \frac{1}{2}r
lateral magnification m=yy=ssm = \frac{y^{\prime}}{y} = - \frac{s^{\prime}}{s}
lateral magnification using curvature radius yy=r/2s(r/2)\frac{y^{\prime}}{y} = - \frac{r/2}{s - \left( r/2 \right)}
Spherical mirror.

Lenses

name equation
refraction on a single surface n1s+n2s=n2n1r\frac{n_{1}}{s} + \frac{n_{2}}{s^{\prime}} = \frac{n_{2} - n_{1}}{r}
magnification due to a refracting surface m=yy=n1sn2sm = \frac{y^{\prime}}{y} = - \frac{n_{1} s^{\prime}}{n_{2}s}
lens maker equation 1f=(n1)(1r11r2)\frac{1}{f} = \left( n - 1 \right) \left( \frac{1}{r_{1}} - \frac{1}{r_{2}} \right)
thin lens equation 1f=1s+1s\frac{1}{f} = \frac{1}{s} + \frac{1}{s^{\prime}}
optical power P=1fP = \frac{1}{f}
effective focal length of two lenses 1fef=1f1+1f2\frac{1}{f_{ef}} = \frac{1}{f_{1}} + \frac{1}{f_{2}}
optical power of two lenses Pef=P1+P2P_{ef} = P_{1} + P_{2}
subtended angle for the eye θ=ys\theta = \frac{y}{s}
subtended angle for near point θ=yNP\theta = \frac{y}{NP}
subtended angle with lens θ=yf\theta = \frac{y}{f}
lens angular magnification (or amplification) M=θθo=NPfM = \frac{\theta}{\theta_{o}} = \frac{NP}{f}
microscope objective lens lateral magnification mo=yy=Lfom_{o} = \frac{y^{\prime}}{y} = - \frac{L}{f_{o}}
ocular lens angular magnification Me=xppfeM_{e} = \frac{x_{pp}}{f_{e}}
microscope angular magnification M=moMe=LfoxppfeM = m_{o}M_{e} = - \frac{L}{f_{o}}\frac{x_{pp}}{f_{e}}
telescope angular magnification M=θeθo=fofeM = \frac{\theta_{e}}{\theta_{o}} = - \frac{f_{o}}{f_{e}}
Convex Lens.
Concave Lens.
Microscope diagram.
Telescope diagram.

Physical optics

Two slit interference

name equation
phase difference due to the difference in the optical path traveled δ=Δrλ2π=Δrλ360 C\delta = \frac{\Delta r}{\lambda} 2\pi = \frac{\Delta r}{\lambda} 360\ ^{\circ}\mathrm{C}
two-slit interference maxima dsinθmax=mλ,m=0,1,2,d \sin \theta_{\max} = m\lambda,\quad m = 0,1,2, \ldots
two-slit interference minima dsinθmin=(m12)λ,m=1,2,3,d \sin \theta_{\min} = \left( m - \frac{1}{2} \right)\lambda,\quad m = 1,2,3, \ldots
two-slit phase difference δ2π=dsinθλ\frac{\delta}{2 \pi}= \frac{d \sin \theta}{\lambda}
distance on the screen to the m-th bright fringe ym=mλLdy_{m} = m \frac{\lambda L}{d}
intensity as a function of phase difference I=4I0cos212δI = 4 I_{0} \cos^{2} \frac{1}{2} \delta
Two slit diagram.

One slit diffraction

name equation
intensity null values asinθ=mλ,m=1,2,3,a\sin \theta = m \lambda, \qquad m = 1,2,3, \ldots
zero intensity minima tgθ1=y1L\tg \theta_{1} = \frac{y_{1}}{L}
diffraction intensity of a slit I=I0(sin12ϕ12ϕ)2I = I_{0} \left( \frac{\sin \frac{1}{2} \phi}{\frac{1}{2} \phi} \right)^{2}
Single slit diagram.

Quantum optics

name equation
equation for photon energy E=hf=hcλE = hf = \frac{hc}{\lambda}
hc product hc=1240 eVnmhc = 1240\ \mathrm{eV \cdot nm}
photon energy ΔE=hf\vert \Delta E \vert = hf
emitted wavelength λ=cf=hcΔE\lambda = \frac{c}{f} = \frac{hc}{\vert \Delta E \vert}