codev.txt Tue Jan 28 18:15:24 2003 1Start Code V by double-clicking the Code V icon on the PC adjacent tothe storage cabinet.Title the lens using the "Lens -> Title" menu item. Something like"Ay 105 achromatic doublet" would be a good choice.Go to "Lens -> Wavelengths" and indicate that you want to enter threewavelengths. Specify a red, green, and blue wavelength in nanometers(e.g. 750, 550, 400). Other fields in this dialog box can stay at theirdefault values.Click on "IMG" in the input window. Go to the "Surf -> Insert -> Surface"menu item and insert 3 surfaces. The input window will then include linesfor STO and 2-3. STO represents the aperture stop. For our lens, the stopis surface 1, so this is OK. You will enter the surface properties for thelens surfaces on these lines.Go to "Display -> Draw Lens -> Auto Draw On" to turn on automatic drawingof the lens.Specify the lens as follows. Make sure everyone in your group gets tospecify part of the lens:Surface Radius Thickness Glass RMD ApertureSTO 203.94 11.94 BK7_SCHOTT REFR 31.752 -156.41 8.86 SF2_SCHOTT REFR 31.753 -569.57 343.67 REFR 31.75The "RMD" column specifies whether the surface is reflective or refractive.BK7 and SF2 are types of glass, and Schott is the manufacturer.Specify that we want to trace f/5.6 rays through the system by going tothe "Lens -> Pupil Specification -> f/number" menu item and specifyinga F/N falue of 5.6.Save your lens definition by clicking the "Save / Restore" button inthe blue input window. Hit "3" for "Save" and specify a filename. Thesoftware will add ".len" to the end of the filename you specify and savethe lens definition in C:\CVUSER.You can see a lot of data about the lens you have entered by going to"Display -> List all lens data" and reading the command window (go tothe "Window" menu to bring it up, if necessary.)We would like to evaluate chromatic aberration of this doublet. We’lldo that by producing a spot diagram in front of, at, and behind the nominalfocus. Go to "Lens -> Other specification -> Through focus definition"to define the focus positions we want to look at. We’ll look at threepositions, starting position -1.5, increment 1.5 (so we the nominal focus,plus 1.5 mm in front and behind).Having done that, go to "Image -> Quick spot diagram". The three spotdiagrams will appear in the "P1" plot window. (Use the "Window" menu tobring it forward if it doesn’t pop up.)Print the spot diagram using "File -> Print." You can print from the PC on the left. If you need to print from the one on the right you will have to copy files to disk or FTP them over. As a last resort you can use the printer in 03 Robinson (Milan and Melissa’s office) -- it’s called hp03. The lab printer is color, but the 03 Rob one is black-and-white -- it will use different symbols for the three wavelengths rather than pretty colors. Which focus setting is best for red? Green? Blue? What does thistell you about the achromatic doublet?codev.txt Tue Jan 28 18:15:24 2003 2Now, let’s make a field map showing the rms spot size as a functionof x and y field angle. That is, we’ll see how the image of a point growsas we move off-axis. Go to "Analysis -> Field Map" and go to the blueinput window. Hit "Enter" on the first and second pages to accept thedefaults. Under "FFD" on the third page, hit "6" to specify RMS SpotDiameter, then hit enter to accept the rest of the settings on page 3.Hit enter again on page 4. On page 5, hit "4" under FCO to specify thatwe want a range of field angles, and specify the X and Y field anglesas having a minimum of -10 degrees and a maximum of 10 degrees. Then,hit the "green light" on the toolbar to tell it to "go" and produce theplot. Print it, if you like, and note your observations.You can perform other analyses by exploring menus. Remember to hitthe "green light" after setting the parameters, and look for plots in theplot window and textual results in the command window.If you want to add off-axis rays to spot diagrams and raytraces, youcan add them from the "Lens -> Wavelengths" menu by specifying morefields. Is the focal surface of the achromat a plane?When you’re ready to enter the singlet lens, reset Code V with"File -> Clear Lens" and specify wavelengths, the entrance pupil, andsurfaces as you did before. Conduct the analysis requested in thelab handout, and any others that you want to do. The"Image -> Quick Best Focus" menu may help you evaluate focus. Note thatit finds the best focus for each wavelength being studied, and weightsthem according to the weights in the "Lens -> Wavelengths" menu. Itexpresses them relative to the "reference wavelength" specified there.To get the focus shift from the reference for a single wavelength, setthe weights for the other wavelengths to zero.To set up the spherical mirror, reset Code V with "File -> Clear Lens."Set a single wavelength of 550 nm and an entrance pupil diameter of 50 mm,using the "Lens -> Wavelengths" and "Lens -> Pupil Spec -> Entrance PupilDiameter" menus. Insert 3 surfaces:Surface Radius Thickness Glass RMD ApertureSTO 600 252 -1000 0 REFL 253 -500 25Now, specify the tilt of the mirror by clicking on its line in theinput window and then clicking "Surf. Data." Hit "4" for decenter,Make sure "Surface number" is "2" for the mirror and "type" is "1"for decenter and tilt. Specify an A-tilt of however many degrees youmeasured the mirror tilt to be.Repeat this for surface 3.You can now draw the lens and perform other analyses as you did