In order to create "Prism," Katy Perry's upcoming October release, the pop star had to step out of the dark and into the light.Perry has been frank about finding herself in a dour place following the unraveling of her marriage to British comedian Russell Brand, and for a while it sounded like "Prism" was going to be a somber reflection of that tumultuous period in her life.When she first went into the studio to work on the record last November, she hadn't yet "let the light in," as the 28-year-old told Billboard magazine.But after some traveling and self-reflection -- it sounds like she really got into Eckhart Tolle around this time -- Perry found a brighter, cathartic groove."I didn't want to do 'Teenage Dream 2.0,'" Perry said, referring to her chart-topping 2010 record. "'Teenage Dream' was highly conceptual, super-pop art. 'Prism' is more organic, au naturale, vulnerable and honest, but still has the same amount of fun."On it, fans'll find a heavy '90s influence, some of which can be heard on Perry's newest "Prism" reveal, "Walking on Air."Working on "Prism," Perry told Billboard that she was "really inspired by this little six-minute thing by Eckhart Tolle where he speaks about loss (in 'The Power of Now'). When you lose something, all your foundations crumble -- but that also leaves a big hole that's open for something great to come through.""Prism," which also features the No. 1 single "Roar," is slated for release on October 22.