THERE can be no nicer person in the upper rungs of the music industry than Jean-Michel Jarre who headlines the opening celebrations of the new Hong Kong Stadium on Friday. On meeting the engaging Frenchman, one doesn't come away with one's head reeling with the mindless pap that's the staple diet of most pop interviews. Jarre is passionate towards his art and deeply caring about his audience. ''Maybe it's not the attitude that prevails generally in the pop business,'' he asserts, ''but I really do care that people who come to my concerts go away with a special experience.'' With this in mind, Jarre's performances which take months to prepare and rehearse - what with employing synthesisers, lasers and other hi-tech wizardry - are geared towards the specific audience. Thus for Hong Kong he has devised a show which (though the contents are still a secret) will, he told Keeping Posted, draw on images of the territory going back to the 1930s and '40s. He will also use the Hong Kong concert to introduce to the world a laser harp - an instrument he has invented together with the help of a team of engineers. With the zeal of a latter-day missionary, Jarre talks fervently of using music to open frontiers. He says: ''I was the first Western musician to play in China and I would also like to perform in Cuba while Fidel Castro is still in power.'' His chance for musical proselytising on a grand scale will come next year which the United Nations has decreed the Year of Tolerance. As a newly appointed goodwill ambassador for Unesco, he has been invited by the international body to perform on all five continents at venues of his choosing. And Jarre has no intention of going for the soft options. Another date - 1997 - has also been pencilled into his busy diary. ''I would love to do a concert in Hong Kong on the night it is handed over to China,'' he exults. Unlike Friday's concert, which is contained within the stadium, for the 1997 show - if it comes off - he says he'll use ''the whole of Hong Kong as my stage''. He adds with relish: ''It will be the ultimate Jean-Michel Jarre concert.''