Real-time holography is a second method of creating holographic interferograms. One can interpret optical phase conjugation as being analogous to a real-time holographic process. One requirement of holographic projection is a laser. They also often find application in holographic optical tweezers. The US military employs headgear with displays for soldiers using a technology called holographic optics. Later, photolithographic techniques created gratings from a holographic interference pattern. The digipak has reflective/holographic cover art. Phase is critically important to adaptive optics and holographic systems. Weapons&colon; Lasers and holographic afterimages. The fringes are similar to those obtained in holographic interferometry. Subjects frequently describe their experience as panoramic, 3-D or holographic. The arcade machine's monitor displayed vector graphics overlaying a holographic backdrop. She can refract lightwaves to create holographic images. The next year, Sega began providing the 3D imaging for Hatsune Miku's holographic concerts. Gabor also developed a mathematical model for demonstrating a holographic associative memory.