In accordance with the present disclosure, a system and method for providing a battery back-up unit for a rack-level power infrastructure is described. The incident optical system comprises an infinite optical system along a main scanning direction and a finite optical system along a sub-scanning direction. When the engine is to be stopped, an adsorption increasing operation for increasing the amount of ammonia adsorbed by the ammonia selective reduction-type NOx catalyst is executed over a predetermined period before the engine is stopped. A flex circuit provides the necessary electrical connections to the electrically isolated electrodes of the piezoelectric ceramic layer. After a current I1 of a first current value not less than an oscillation threshold is injected to a semiconductor laser gyro, a current I2 of a second current value smaller than the first current value is injected. The subject is to provide an AM device that has a short response time, a large voltage holding ratio, a large contrast ratio, a long service life and so forth.