The Brooklyn Academy of Music plans to open a third theater space that will allow the performing arts presenter to expand its programming to include emerging artists and technologically complicated interdisciplinary offerings.

Venue will be a 263-seat black box with a flexible layout, housed in a building to be located behind BAM’s Gilman Opera House in Fort Greene, Brooklyn. Building will be named after the late BAM supporter and former Morgan Stanley honcho Richard B. Fisher.

BAM leadership hopes to have the venue open by sometime in 2013. Theater will be used for BAM programming during half the year and will be made available for community arts use the other half.

BAM’s two existing venues for legit fare are the 2,000-seat Opera House, home to the preem of the Sam Mendes-helmed Bridge Project double bill, and the 875-seat Harvey Theater. Unlike the new space, those two venues are traditional proscenium houses.

BAM exec producer Joseph V. Melillo said the new, technologically up-to-date facility would help him augment the variety of stage work that could be presented at BAM. “Into that space I can invite the art made in the 21st century, which is not about the proscenium arch,” he said.

He added the space would allow BAM to host artists-in-residence, whose work could be shown on the new stage.

Community access to the venue will be offered at a low cost, with Melillo saying he already has begun talks with donors about funding subsidies for community arts groups that present in the space.

Melillo and BAM prexy Karen Brooks Hopkins first hatched the idea of a third stage about five years ago. Plan is to break ground on the Fisher building in the fall.

Facility is designed by H3 Hardy Collaboration Architecture, with the firm Auerbach Pollock Friedlander consulting. Lobby of the building will be named after Peter Jay Sharp. the theater space itself will be called the Samuel H. Scripps Stage, with the interior of the theater dubbed the Judith R. and Alan H. Fishman Space.

Although it comes at what seems an economically inauspicious time, the announcement is part of the launch of a $300 million fund-raising campaign for BAM, which has $160 million already in the bank from both individuals and foundations, according to Melillo.

At almost 150 years old, BAM already has a busy programming sked, including the Next Wave Fest of international performances every fall.