Useful Optical Formulas

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Useful Optical Formulas
(Prepared by : Gener Gatmaitan, 6/4/2012 for ios Optics^TM)

	Reflection Factor
	P = 2n/(n² + 1)			n is the refractive index of glass
	Refractive index of glass			@ Helium (587.6nm) d line		=
	Reflection Factor					=

	Optical Density and Transmission
	D_(ג) = Log 1/T_(ג)			D is the optical density and T is the transmittance
		Optical Density (D_(ג))				=
		Transmittance (T_(ג)), given D_(ג)				=	%
		Transmittance (T_(ג))				=	%
		Optical Density (D_(ג)), given T_(ג)				=

	Abbe Number
	vd = (nd – 1) / (nF – nc)			v_d is the abbe number
				n_dis the refractive index at H_e line (587.6nm)
				n_Fis the refractive index at H line (486.1nm)
				n_cis the refractive index at H line (656.3nm)
	Refractive index at H_e line (587.6nm)				n_d	=
	Refractive index at H line (486.1nm)				n_F	=
	Refractive index at H line (656.3nm)				n_C	=
	Abbe Number				v_d	=

	Temperature Conversion
	Farenheit to Celcius			^oF		=	^oC
	Celcius to Farenheit			^oC		=	^oF

	Glass Combination Transmittance (assume adhesive index matched to glass)
	External Transmittance of 1st glass				T₁	=	%
	External Transmittance of 2nd glass				T₂	=	%
	External tranmittance of combination						%

	Internal Transmittance of glass
	K_x= Ln (T₁/T₂) / (t₁– t₂)			K_xis the absorption ratio
				T₁is the external transmittance at thickness t₁
				T₂is the external transmittance at thickness t₂
				t₁is the glass thickness with T₁ transmittance
				t₂is the glass thickness with T₂ transmittance
			τ = ℮ ^{(thickness x Kx)}	τ is the Internal transmittance
	Glass thickness				t₁	=	mm
	External transmittance				T₁	=	%
	Glass thickness				t₂	=	mm
	External transmittance				T₂	=	%
	Thickness of glass				t₃	=	mm, (values from t₁ ~ t₂)
	Internal Transmittance				τ	=	%

	Glass Thickness vs Transmittance
	Thickness of glass (catalog thickness)				t₁	=	mm
	Refractive Index (catalog value)				n	=
	Internal Transmittance at t₁(catalog value)				τ₁	=	%
	Computed Reflection Factor				P	=
	Transmittance with known thickness of glass
	Thickness of given glass				t₂	=	mm
	Internal Transmittance at thickness t₂				τ₂	=	%
	External Transmittance of glass at t₂				T₂	=	%
	Thickness Calculation with known glass transmittance
	Desired External transmittance of glass				T₃	=	%
	Computed Internal Transmittance				τ₃	=	%
	Thickness of glass at transmittance T₃				t₃	=	mm

Useful Optical Formulas

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Useful Optical Formulas

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Santa Clara, CA 95054