See adaptive optics, speckle imaging and optical interferometry. Conformational changes can be measured using circular dichroism or dual polarisation interferometry. Birefringence of lipid bilayers can be measured using dual-polarization interferometry. SAR Tomography is a subfield of a concept named as multi-baseline interferometry. OCT is based on low-coherence interferometry. Dual polarisation interferometry provides complementary information about surface captured proteins. Other methods include the AC Josephson effect and photon recoil in atom interferometry. Measurement in biology using wave guide techniques, such as dual-polarization interferometry, is another example. This allows interferometry depth measurements to be combined with density measurements. It aims to measure gravitational waves directly by using laser interferometry. This technique is known as live holographic interferometry. The fringes are similar to those obtained in holographic interferometry. Volcano and earthquake monitoring use differential interferometry. This was accomplished by using the satellite in conjunction with ground-based observatories and interferometry techniques. In 1946, a technique called astronomical interferometry was developed.