This tutorial examines how Airy disk size changes with numerical aperture and wavelength; it also simulates the close approach of two Airy disks. Instructions for operation of the tutorial are outlined immediately below the applet window.

	Interactive Java Tutorial
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To operate the tutorial, use the sliders to change both the wavelength of illumination and objective numerical aperture. The applet window default state contains two Airy disks separated by distance D, with an illustration of their intensity distributions immediately below the disks. Use the wavelength slider to vary the wavelength from 700 nanometers down to 400 nanometers. Airy disk size will become smaller with decreasing wavelength. The slider on the right controls objective numerical aperture. Airy disk size will decrease with increasing numerical aperture. The bottom slider controls the distance (D) between the Airy disks. Moving the slider to the right causes the disks to approach each other, stopping at the limit of resolution. The simulated light cone increases in size with increasing numerical aperture