Luxpop    Index of Refraction, Thin film, Optical computing          

Previous blog entries>>
Custom code entry
Return n for Au in steps of 100 nm in .csv format using full array computation. Display using disp()

Full coding guidelines and material references
Selected functions currently supported:

* ret_n, ret_k: return n or k for material

Click on link to auto-fill code entry window with desired material: GaAs , GaN , Si , Ge , Al2O3 , ITO , SiO2a , Si3N4 , Cr , Fe , Ni , Cu , Ti , Au , Al , Mo , SN16_300 , SN18_300 , SN20_300 , SN40_300 , AZO , ZNO_NR_TOP , ZNO_NR_BOT , Au_NANO1 , Au_NANO2 , Ag_NANO1 , Ag_NANO2 , AgLPHP , ITO_NANO , PPX_Ag_5 , PPX_Ag_7 , PPX_Ag_9 , PPX_Ag_11 , PPX_Ag_15 , PPX_Ag_0 , KNTN_1 , p1985_6Au_5Kap_8nn , ATO , CH3NH3PbI3 , As2S3

Index of Refraction
* Return the refractive index of a (fixed ratio) substance at a given wavelength,l (nm). Further information also may be given.
* The absolute refractive index (i.e. with resp. to vacuum) is returned, unless stated otherwise. Click here for more index of refraction terminology.
* See also our Long List of Index of Refraction Values (A-Z)... for other materials.
     l:nm       temp deg C     
variable compound: return index of refraction of variable atomic content compound materials at a given wavelength, l (nm), and material content proportion, x.
* For quaternary materials such as InGaAsP or AlGaInAs, Luxpop assumes there is a lattice match to InP ==> no need to specify a value for y since entering a value for x will force a value of y.
* For H2SO4 (sulfuric acid) and HNO3 (nitric acid), x relates to the wt % of these substances in water. e.g. x=0.4 for H2SO4 means a 40% ratio of H2SO4 by weight in an aqueous solution.

Substance:    l: nm      (x:      temperature:  deg C   

Light at Interface

Thin film stack model: reflectivity/transmissivity online calculation for light incident at an arbitrary angle on a thin film stack.
The algorithm returns full reflected/transmitted field, power, and phase information for incident TE (perp, or s) There are up several sets of information to be entered:
    1 Incident angle, centre wavelength(lambda), wavelength(lambda) sweep range, and number of points(max 20) to compute across the wavelength sweep range.
    2 Complex index of refraction of incident medium (n,k). For air, n=1 and k=0 is a good approximation.
    3a Thin film stack. Enter stack information using the following notation, where the top film is closest to the incident medium (see examples below):
Fixed index on each layer: notation Fully dispersive calculation: notation Variable thickness: notation NEW! Convenient repeated H/L film notation: great for repeated high/low in thin film stacks
thickness1, n1,k1
thickness2, n2,k2
thickness3, n3,k3
thickness1, {Material1}
thickness2, n2,k2
thickness3, {Material3}

Deposition materials currently available are: Ag,Al,Au,Cr,Cu,GaAs,ITO,Mo,Ni,Si,Si3N4,SiO2a,Ti. (SiO2a is amorphous SiO2)
Contact Luxpop to get your favourite material added.
NOTE: if '{ }' characters do not work on your system, use '( )' characters.
In lieu of one thickness, put semicolon-separated values in parentheses. Up to 3 sets are permitted.

thickness1, n1,k1
(thickness2a;thickness2b;thickness2c), n2,k2
(thickness3a;thickness3b;thickness3c), {Material3}

In this example, three sets of calculations are performed.
Set 1 has: layer 1 thickness1   layer 2 thickness2a   layer3 thickness3a
Set 2 has: layer 1 thickness1   layer 2 thickness2b   layer3 thickness3b
Set 3 has: layer 1 thickness1   layer 2 thickness2c   layer3 thickness3c
In box 2a, define the "H" and "L" films. In the main entry box 3a, it is then much easier to define alternating stacks and adjust quickly.
4 Complex index of refraction of substrate (ns,ks): either enter a fixed value OR leave the ns,ks fields blank and choose a substrate material for a fully dispersive calculation.
Luxpop can usually do more layers or steps for fixed index layers compared to dispersive material layers, depending on system activity.
    Here are some examples of thin film stacks. Feel free to cut and paste into the " 3a" box below.
Example#1: Fixed index layers(Born & Wolf, Principles of Optics, 9th Ed. p. 74) stack of 1/4 wavelength (for lambda=546 nm) High n / low n materials at n= 2.3 and 1.35

Example #2: Specify material using {Material} notation on some or all the layers to obtain dispersive calculations. Cut and paste into box #3a below.

Example #3: Variable thickness notation on one layer to perform multiple sets of calculations simultaneously. Cut and paste into box #3a below.

NEW! Example #4: predefined H/L layers. Define H and L films in boxes 2b below, then use those in your stack definition. Example below is equivalent to example #1 on the left, if H=> 59.348,2.3,0 and L=>101.11,1.35,0. Cut and paste into box #3a below to try.


1 incident angle (theta_i): deg     centre_lambda: nm    lambda sweep range: +/-nm     # sweep pts:
2a index of incident material (eg air) n:     k:

2b Predefined layers:   H:     L:    

3a Enter the thin film stack text information into the box below
3b Optional: custom power spectral profile of input.
* If centre_lambda in section 1 above is kept blank, the information in this box to the right will be used and will override the wavelength sweep range and the # of points.
* Max 15 wavelengths.
* Wavelengths must be monotonically increasing, but do not need to be uniformly spaced.
* Input power must be in linear units. Output power will be in the same units as input power.
* Format as follows:
Feel free to overwrite sample text in box==>

4 index of susbtrate material (eg glass) ns:     ks:     >OR
  leave the ns,ks fields blank and select a substrate material:   

Here is another simple example:
Example#2: (Born & Wolf, Principles of Optics, 9th Ed. p. 757) Single layer metal film with thickness = 300nm, n=3.5,k=0.1


Arbitrary reflection on complex material. Calculate the reflected amplitude coefficients and phase shifts for linearly polarized light at an arbitrary polarization azimuth angle, incident at an arbitrary angle on a material of arbitrary real or complex index of refraction. Two sets of results are given: ideal zero smoothness and rough surface, with impact calculated per the Kirchoff approximation.
In the inputs below:
(i) n1 and k1 are respectively the real and imaginary values of the index of refraction(incident material), (ii) n3 and k3 correspond to the transmitted material, (iii) theta_i is the incident angle measured from the normal, (iv)angular sweep range is the angular range, centered on theta_i, across which the program will perform angle calculations, (v) d is the rms surface height in nm (vi) lambda is the wavelength at which the impact of surface roughness is calculated, and (vii) num sweep points is the number of points that will be computed during the sweeping.
(For the example given below, the default values below will allow the user to locate the approximate Brewster angle for BK7 in the visible.)

n1:     k1:     n3:    k3:    theta_i: degrees    d : nm     lambda: nm
angular sweep range: degrees      num sweep points: (max 25)       

Click here for more optical computing features.