The latest from Finnish composer Kaija Saariaho is a gut-wrenching opera about the rape of a strong-willed woman by a soldier living in an unspecified war zone. “Ms. Saariaho has said that the idea for this opera came to her when she was pregnant and saw a sonogram of her baby… And pregnancy can be experienced as an invasion by the ultimate other, a metaphor that resonated with [her librettist’s] ideas about cultural clash.”