On a giant screen a towering wall of flame dwarfs the silhouette of a woman standing before it. The sense of elemental power confronting this fragile figure of humanity is more than a little scary. She raises her arms, looks to the sky and falls backwards into a perfectly still body of water. Swirls of orange and yellow flame are reflected in the dark water, like a painting that moves, and she disappears.

Unlike the cool detachment in much contemporary art, a film by Bill Viola is an intense emotional experience. He deals with universal stuff on a grand scale: love and death portrayed on a plasma screen 60 feet high.

His latest series of work on show at the Haunch of Venison galleries in London is based on Wagner's opera Tristan und Isolde, about the adulterous love, ignited by a love potion, between Isolde, the wife of the King of Cornwall, and the knight Tristan.

Viola has said: 'It is the story of a love so intense and profound that it cannot be contained in the material bodies of the lovers. In order to fully transcend their love, Tristan and Isolde must ultimately transcend life itself.'

Using symbolism from Wagner's opera, he portrays these powerful emotions through a series of films that are quite overwhelming in scale and spectacle.

In 'Tristan's Ascension' a figure wearing a white shroud lies on a stone slab in a room that looks like an ancient temple. Water starts to drip around the figure. What is strange is that the droplets move upwards from floor to ceiling. Drops become a torrent of water flowing in reverse which lifts the figure from the slab slowly raising him heavenwards. The effect is breathtaking, like witnessing a miracle. And it is this sense of somehow being there, in the presence of divinity, that makes Viola's work so mesmerising.

Yet despite the deeper meanings, the process of filming is no different to any large scale Hollywood production. The scenes for 'Tristan's Ascension' required hundreds of gallons of water and an experienced acrobat. The footage was then run in reverse and slow motion.

What makes Viola's films such a pleasure is the beauty of their surface. The aesthetic is of painting. In 'Passage into Night', the patterns of a woman's robes shift and shimmer in the parched desert landscape, creating an effect that is as sensual as any abstract expressionist painting. That the films are shown largely in slow motion adds to their visual poetry. Underwater figures that presumably would be thrashing and gasping in real time appear to be performing an elegant sub aqua ballet, which also expresses the existential struggle. The slowing down of time is an important part of Viola's work. 'When you slow something down, you're in more of a dream space, an internal subjective space,' he has said. He wants to take us out of our material reality, the surface of the everday, to a place that is more profound.

In Purification a tiny dot of light flickers in the far distance. Very gradually it becomes larger, the flickering morphs into the discernible motion of a human gait. The light and movement is ethereal. There is no substance to the figure. Slowly a tangible presence appears in the distance walking over the horizon until she arrives, dominating the screen with her face and the force of her glare. This film feels like a meditation on the cycle of life and draws the mind to the transient state of existence. When slowed down like this, every movement and facial expression becomes more meaningful; we experience it fully rather than as a fleeting prescence.

Despite the cutting edge technology, plasma screens, high definition and Hollywood scale production, Viola's work has old fashioned values. They are beautiful to look at, sublime even. And these days the way we understand images means it's not cool to believe your work can truly mean what you want it to, particularly when that meaning is transcendental.

Viola is an unashamed pursuer of profound spiritual meaning. The absence of cyncism or irony can be moving, indeed some films made me want to cry - although there were times I felt like I was watching a perfume ad. Even so watching the suffering of the woman in 'Purification', as she goes through a ritual of transformation and rebirth, it is hard not to feel sad. And it's no detached pity. She appears a representative of universal woman, a bearer of the pain that all of us experience at times.

LOVE/DEATH: The Tristan Project is at the Haunch of Venison, London, W1 until 2 September