I see. With some modification of this idea, you invent LIGO. Instead of using two masses as a "slit", the light is bounced between the two masses many times, mu

I see. With some modification of this idea, you invent LIGO. Instead of using two masses as a "slit", the light is bounced between the two masses many times, multiplying the tiny change in distance between the masses induced by the gravitational wave.