定义：
谐振腔或者波导的横向模式，不包含基模。

光学谐振腔和波导中传输的模式可以具有不同的强度截面和传播常数，这一特性也可以从横向模式中体现出来。强度截面最简单的模式称为基模，而其它的则称为高阶横向模式。

并不是所有波导都包含多个模式，不包含的称为单模波导（例如，单模光纤）。

Definition: transverse modes of a resonator or waveguide, excluding the fundamental (axial) modes

Alternative terms: transverse modes, lateral modes

More general terms: modes

Opposite term: fundamental mode

The modes of some optical resonator (resonant cavity) or the propagation modes of a waveguide can have different transverse intensity profiles and propagation constants, and this aspect is emphasized by the term transverse modes (or lateral modes). Those modes with the simplest intensity profile are called fundamental modes, and all others are higher-order transverse modes. The fundamental mode of a waveguide is the one with the highest effective refractive index.

Not all waveguides support higher-order modes, at least not within their guided modes; they are then called single-mode waveguides (e.g. single-mode fibers).

Laser oscillation on higher-order modes as well as lights transmission in higher-all modes of the waveguide are associated with decreased beam quality.

The article on modes gives more details.