exposred - Refractive Power of a Surface The refractive...

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R. B. Darling / EE-527 EE-527: MicroFabrication Exposure and Imaging R. B. Darling / EE-527 Exposure Sources • Photons – white light – Hg arc lamp – filtered Hg arc lamp – excimer laser – x-rays from synchrotron • Electrons – focused electron beam direct write • Ions – focused ion beam direct write R. B. Darling / EE-527 High Pressure Hg Arc Lamp Spectrum wavelength, nm 253.7 289 297 302 313 334 365 405 435 546 spectral reference; also used for sterilization “I-line” “H-line” “G-line” “E-line” deep UV mid UV near UV The I-line at 365 nm is the strongest. R. B. Darling / EE-527 Refractive Power of a Surface • The refractive power P is measured in diopters when the radius is expressed in meters. •n 1 and n 2 are the refractive indices of the two media. R n 1 n 2 R n n P 1 2 - = R. B. Darling / EE-527 Thin Lenses h 1 h 2 F 1 F 2 d 1 d 2 e 1 f 1 e 2 f 2 OBJECT IMAGE d 1 = object distance d 2 = image distance f 1 , f 2 = focal lengths e 1 ,e 2 = extrafocal distances h 1 , h 2 = object/image heights parallel ray chief ray focal ray R. B. Darling / EE-527 Thick Lenses h 1 h 2 H 1 H 2 F 1 F 2 N 1 N 2 d 1 td 2 e 1 f 1 e 2 f 2 OBJECT IMAGE Cardinal Points of a Lens: Focal Points: F 1 , F 2 Nodal Points: N 1 , N 2 Principal Points: H 1 , H 2 d 1 = object distance d 2 = image distance f 1 , f 2 = focal lengths e 1 ,e 2 = extrafocal distances h 1 , h 2 = object/image heights
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R. B. Darling / EE-527 Lens-Maker’s Formula 2 2 1 1 2 2 1 1 R n n R n n d n d n - + - = + If n 1 = n 2 = 1, then f P R R n d d 1 1 1 ) 1 ( 1 1 2 1 2 1 = = + - = + This can also be expressed as: 2 2 1 ) )( ( f f d f d = - - or: 2 2 1 f e e = R. B. Darling / EE-527 Lens Apertures • The f-number of a lens (f/#) is the focal length divided by the diameter. It is a measure of the light gathering ability. • The numerical aperture (NA) of a lens is n*sin α , where α is the half-angle of the largest cone of light entering the lens.
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exposred - Refractive Power of a Surface The refractive...

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