TAG Lens: Revolutionizing Optical Microscopy With Ultra-High Speed Variable Focus

Abstract

The Tunable Acoustic Gradient Lens, or TAG Lens, is a revolutionary innovation that uses sound waves in liquid to provide the fastest variable focus lens in the field of adaptive optics. Capable of scanning a wide range of focal lengths in microseconds, the TAG lens is orders of magnitude faster than other liquid lenses, optical membrane or mechanical scanning approaches presently available on the market [1]. The award-winning TAG Lens functions by using a piezoelectric element at the boundary of a cylindrical cavity to excite high frequency acoustic pressure waves in a confined liquid. The corresponding oscillations in liquid density create an index of refraction profile like that of a simple aspherical lens (Figure 1). However, unlike static devices that rely on the deformation of a surface or interface, the TAG Lens is a tunable gradient index of refraction (GRIN) lens that does not require any mechanical motion or redistribution of liquid to change its optical properties, allowing it to modulate focal length at very high speeds (70kHz to 1 MHz). Furthermore, the aspheric nature of the index of refraction profile results in a tunable lens with little to no spherical aberration, making it an ideal candidate for high-speed, high-precision applications [2].