Violinist Jennifer Koh. (Juergen Frank)

The play of light — that weightless, ephemeral stuff, so much like sound itself — has long fascinated composers, particularly the musical impressionists of early 20th century France and the “spectralist” composers of the past few decades. So it was a particularly luminous evening at the Library of Congress on Friday, when violinist Jennifer Koh, cellist Anssi Karttunen and pianist Ieva Jokubaviciute paired the music of Ravel and Debussy with two new works by the Finnish composer Kaija Saariaho — music inspired, as the composer put it, by “the continuous transformation of light.”

Lyrical, mischievous, shifting from snarling to ebullient, Debussy’s 1915 “Sonata for Cello and Piano” is a small-scale tour de force, and Karttunen and Jokubaviciute opened the program with a wonderfully extroverted reading, seething with color and life. It was followed by Saariaho’s “Aure” for violin and cello, a quieter but no less beautiful work whose title refers to “a kind of delicate morning breeze.” Like much of Saariaho’s music, it was intricately etched, drawn more from nature than from human passion, and it seemed to glow with a distant light, as if from the edge of the turning world.

As a cellist, Karttunen has worked with Saariaho for decades, but it was the electrifying young violinist Koh whom the packed house had really come to hear. Conviction, ferocity, an irresistible sense of play — Koh has it all, and she turned in a no-holds-barred performance of Ravel’s “Sonata for Violin and Violoncello” that won her the first of several standing ovations. Debussy’s “Sonata for Cello and Piano,” which followed, may even have been more spectacular: a reading (with the superb Jokubaviciute accompanying) that imbued Debussy’s rapturous sensuality with Koh’s own razor-sharp intelligence and wit.

The evening closed with the Washington premiere of Saariaho’s 2014 trio, “Light and Matter,” inspired by sunlight on trees outside the composer’s window. Like the earlier “Aure,” it’s a naturalistic work that unfolds with a kind of austere purity, building delicate details into a work of huge, elemental power. Even at this small scale, Saariaho’s music inspires a kind of awe — it can be like staring into a vast landscape — and that sense of immensity ran through the entire work: a universe, revealed in a moment of dappled light.