![](data:image/png;base64,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)
義である。
像面上の強度分布を求める為に回折積分を行なう時、任意の面での振幅と位相の分布が分か
れば回折計算は可能であるから、その積分が参照球面上で行なわれるとすれば、実際の光線通過
経路に沿って実波面からその光線が参照球面に到達するまでの光路差を得ることは、妥当なやり方
である。
その光路長差を知る事により参照球面上におけるその光線通過位置での実際の位相が正確に
計算できるからである。こうした回折計算を行う場合には、大抵、参照球面までの光線追跡が行われ
そこまでの光路長が計算されることとなるので、計算或いは理論展開における実用性を考慮した定義
である。
b)
より形式的に考えて、回折積分が等位相面である実波面上で行なわれるとする時、この場合に
は回折積分に際し実波面上の点 Qから観測位置 P’0(回折強度分布を計算する像面上における位
置)までの距離が重要になる。実波面上に2次波源が存在し、そこからの総ての2次波の影響によっ
て測定点における振幅を得ようとすることがホイヘンスの原理を基とする回折計算の理屈であるが、こ
の考へ方における波面収差とは Q、P’0方向に定義されるべきである。より一般的に表現すれば、波
面上の点と測定点を結ぶ線分に沿った∆
W
‘を採用する、と言う事である
。
この線分の参照球面から P’0までの距離は参照球面半径として一定であるから形式的にはこの
線分に沿った実波面から参照球面までの距離が重要になる。この距離を波面収差とする考え方であ
る。
また、実際の波面測定結果などで波面収差の量を示す場合には理想的波面中心へ向けての光
路長差として示される事が一般的である。
前者の計算手法に後者の波面収差量を用いれば位相が可笑しな値になって結果が狂う。また
逆に後者の考え方においては実波面上の点 Qの座標を求める事が最重要になり、波面収差分もここ
に含まれてしまうが、前者の波面収差量の定義を混同して用いる事は、少なくともそれらの誤差の検
討無くしては、筋が通らない。
原理的には明快なのであるが、上記b)の定義においては、光線に沿わない∆
W‘
の計算を総て
の光線に対して実行することは、不規則な 3次元的な波面形状をコンピュータ内で構成することにも
なり、非常に煩雑な作業になる。妥当な計算誤差の内に収まるのであれば∆
W
を波面収差として常に
採用する方がより実際的であって、参照球面中心方向に測った距離を、この Q’を通過し P’へと向かう
光線に沿った距離に置き換えて、一般的には、波面収差は定義される。勿論、そこには上述のように
理論的な根拠が存在するわけであるが。
それでは、ここで、これら二つの定義の違いにより生ずる誤差について考えてみよう。(主に参考
文献1)に拠る。)