ECE 4616 Deslis

1

Introduction• Past Homework solution

• Zemax Examples using Third Order Aberration theory

• Monochromatic Design

• Polychromatic Design

• Homework

ECE 4616 Deslis

2

HomeWorkDesign a single lens using Zemax and show performance using Spot Diagrams

•Focal ratio f/5.6

•Glass is N-BK7

•Focal Length is 100mm

•Field of view is 8 degrees

•Central Lens thickness 2mm to 12mm

•Wavelength 632.8nm (HeNe)

•Edge thickness minimum 2mm

•Lens should be optimized for smallest RMS

•Object is at infinity

ECE 4616 Deslis

3

HOMEWORKSurface (Radius=R1)

concentric to STOP( B=0)

STOP

Aplanatic surface (Radius=R2)

Δ(u/n)=0

Specifications

EFL=150 mm

F/#=5.6

WL=0.55

Find.

1. Refractive index of lens

2. Radii of lens –use Lens Maker formula

3. Determine which aberrations are present for each surface

R2=R1

ECE 4616 Deslis

4

Solution to Homework - 1For the first surface where s1=∞, n=1, n’=μ

Rnn

sn

sn −

+='

''

11

1'1 −=μμRs

For the second surface 11

'12 −=−

−=−=

μμμ RRRRss

Since the second surface is aplanatic then 11'

2 −=

+=

+= μμ

μ RRRn

nns

012 =−− μμ From where we get μ=1.618034

⎥⎦

⎤⎢⎣

⎡ −+−−=

2121

)1(11)1(1RR

dRRf μ

μμ R1=R2=d with f=150 mm we get R=35.4102

ECE 4616 Deslis

5

Solution to Homework - 2

(SI)1

0

0

(SIV)1=X

0

0

0

0

(SV)2

Surface1 Surface2

(SIV)2=-X

TOTAL

(SI)1

0

0

0

(SV)2

ECE 4616 Deslis

6

ZEMAX SetupAdd F/# (EFL Later)

Set up Units

ECE 4616 Deslis

7

Wavelength data

Add Wavelength data

Add FOV

ECE 4616 Deslis

8

Zemax Setup

Add Radius for surface 1Add Radius for surface 2 to be equal to Radius of surface 1Add Thickness equal to the radius for surface 1Add a Glass that will be changed later – Start with N-BK7Then Use glass solve and allow index to vary

ECE 4616 Deslis

9

Zemax Setup

To make it concentric to the STOP we use s thickness solve where the thickness is always equal to the radius of surface 1

Make the second surface aplanatic by using the aplanatic solve on the second surface

ECE 4616 Deslis

10

Zemax Setup

Allow Radius of Surface 1 to vary

Now we have two more things to constrain

1.EFL2.Radius of surface 1 has to be equal to radius of surface 2

These two items will be controlled in the merit function

Find Paraxial focal plane using the thickness solve on surface 2

ECE 4616 Deslis

11

Zemax Setup

ECE 4616 Deslis

12

The Merit Function Setup

EFFL is set to 150 mm

The two curvatures are set to be the same, by subtracting each other first andThen by multiplying that difference with a large number

ECE 4616 Deslis

13

Optimize

ECE 4616 Deslis

14

Set up Merit Function for best focusAllow defocus to vary and add rays in the merit function so that we optimize with respect to RMS spot size

ECE 4616 Deslis

15

Shift from Paraxial to Best Focus

ECE 4616 Deslis

16

Allow for asphericity at pupil

ECE 4616 Deslis

17

Two lenses-Monochromatic DesignGlass is N-PSK53A nd=1.61800

ECE 4616 Deslis

18

Monochromatic Seidel coefficients

ECE 4616 Deslis

19

Add Color

ECE 4616 Deslis

20

Move Stop to correct CT

ECE 4616 Deslis

21

Stop Shift FormulaeII SS =*

IIIII ESSS δ+=*

IIIIIIIII SEESSS 2* 2 δδ ++=

IVIV SS =*

IIIIVIIIVV SESESSESS 32* 3)3( δδδ ++++=

LL CC =*

LTT ECCC δ+=*

These powerful formulae enable us to calculate the effect of a stop shift on the aberrations of any system.

TOTAL

0

0

0

0

SV

ECE 4616 Deslis

22

Add Buried Surfaces

N-PSK3A(620635) and F9(620381) for both doublets

ECE 4616 Deslis

23

Modify Merit Function

ECE 4616 24

Performance of Lens

ECE 4616 25

Remember Project

Homework due next class

Next Homework covers use of Zemaxand is out on Thursday

Selection: Pick your device. If you have no ideas, look on the website at the old examples or come see me. Duplicates are OK. Ihave topics from work I can suggest if you’re interested. This report should give a brief background on what the device is, what it’s good for etc and (important) a list of the relevant external specs with, where possible, guesses on reasonable values.

DUE: October 15th